"I'm a bit ADD, in case you haven't noticed," quips Martin Henderson, flitting around his trailer on the Los Angeles set of Grey's Anatomy. One minute he's asking whether he should grow his hair back, while changing into his television scrubs; the next he's cleaning the kitchen sink while contemplating the key to success, and the dwindling number of summers he has left to learn how to kite-surf.
His philosophical ponderings, sound-tracked by UB40 and Bob Marley, are interrupted by a knock, signalling it's time for makeup - much to the surprise of a publicist, who observes he already looks like he's been "through the works".
"No, wait till you see me in makeup - you'll be so impressed," he laughs.
Rewind two years and Henderson would have felt eased to know such compliments lay ahead as he mused over his upcoming 40th birthday at a Tourism New Zealand event in Beverly Hills, confessing that the life of a Hollywood actor is inevitably accompanied by looking in the mirror and "hoping you don't have new wrinkles."
Today, it's clear he need not have worried.
Ageing aside, after 15 years in Hollywood, Henderson, 41, has risen above rejection, heartache, grief and, at times, becoming the subject of tabloid fodder, to reach a professional peak which just saw him grace the big screen in Everest, wrap playing Jennifer Garner's husband in Miracles From Heaven and debut his biggest American television gig yet, as hot new doctor, Nathan Riggs, on Grey's Anatomy.
He's living the dream - albeit one he didn't realise he had when he moved to LA at 25, visions of movie-making emblazoned on his mind.
"When I came to America I never wanted to do television again," he admits, settling on to the couch. "I grew up doing TV and it's a compromise - there's not enough time to rehearse to a point where you iron out all the problems, so you shoot from the hip and hope for the best, but with film there was a chance to get into it, in a way I'd never experienced.
"Once I tasted that I went, 'Right, I'm never doing TV again.' And I was 25, so the idea of being tied down to one job for more than six months gave me the creeps. I had opportunities and ran from them, fast.
"But after a few years, I was in a hotel room in Vancouver doing Battle in Seattle with Charlize Theron, Ray Liotta and Woody Harrelson - great cast, lead role, subject matter I thought was politically important and just a cool job. I was living the dream I had when I left New Zealand, but by my early 30s I realised that was not a sustainable way of life for me. There were times I'd be away from my dog or girlfriend and it's just a shitty way to live. Always being away started to wear me down and as much as I loved the jobs, I didn't want work to take precedent over my life.
"I realised I needed to go back on my idea of never doing TV."
Cue roles on Off The Map, Secrets & Lies, The Red Road and now popular medical drama, Grey's Anatomy.
His arrival caused controversy with fans still reeling from the death of their beloved McDreamy (Patrick Dempsey), who exited the series last April.
Upon Henderson's casting he was immediately labelled "McDreamy's replacement", yet his role was undeveloped when he took the job following a meeting with TV superpower Shonda Rhimes, who previously hired him for Off The Map.
It wasn't until his first table read that Henderson had any inkling of his character's name or background.
"Shonda offered me the job and I thought, 'Great show, shoots in LA, ticks all the boxes ... Cool.'
"I told my agent I was interested and he asked what the role was. I was like, 'You know what? She didn't actually mention a role.'
"So I called Shonda and said, 'I'm honoured, grateful and thinking about saying 'Yes', but have no idea what I'm saying 'Yes,' to!'
"She was like, 'We'll figure that out.'
"The first time I read anything about my character, was out-loud in front of the writers, producers, crew and cast. It was so nerve-wracking."
In addition to having one of Hollywood's most mighty television producers develop a character for him, he was further delighted when asked to keep his Kiwi accent, confessing that mastering the American accent has been a career-long struggle.
"Then I asked if I could do full-on Kiwi, like Flight of the Conchords, and they were like, 'Maybe not... we do want people to understand you'."
Although Henderson had lunched with his "lovely, wonderful and so candid" co-star Ellen Pompeo prior to starting work, he was relieved to be welcomed with hugs and excitement from the rest of the tight-knit cast.
Called in a week early, his first day was a blur, but he does recall a brief flashback to Shortland Street's Ferndale.
"It was a little surreal being in a hospital again," he grins. "I did have a moment, standing there as crew were setting up where I looked around and went, 'Wow, I'm on a hospital set ... it's the same thing, just thousands of miles away on the other side of the Pacific. I'm doing the same thing!'"
Back then, he was a teen, quietly pursuing a passion most kids would have scoffed at, the seed of which was planted on stage at Birkenhead Primary School.
He was 10 years old and had just completed his first play, walking off stage on a high that would shape the rest of his life.
"I remember lying in bed and I would never have admitted this to anyone because of the whole tall poppy thing - I was aware if I vocalised my dreams there would be someone quick to tell me I couldn't or shouldn't - but I had just done that play and thought, 'Acting ... that was fun!'
"Of course, as a little kid you go, 'Hollywood!' just like a boy scoring his first try goes, 'All Blacks!'
"Then in 4th form at Westlake [Boys' High School], I had done my first TV show [Strangers], but [acting] wasn't something that was encouraged. I was trying to hide it. It was a rugby and rowing school, so I focused on academics. The acting, I was almost ashamed of."
His former teacher, Louis Borok, admits that after Henderson ditched his French homework to audition for Shortland Street, he told him he was unlikely to make a career as an actor. "So much for my ability to spot talent."
But spurred on by encouragement from another teacher and the unwavering support of his mum, Veronica, Henderson, whose parents divorced when he was 5, clung to his acting dreams.
He started on Shortland Street at 17 as Stuart Neilson, rapidly becoming a teen heart-throb - gracing magazine covers, bedroom walls and experiencing a level of fandom these days reserved more for pop stars.
"I remember driving him somewhere in the early days and as we parked, a hoard of screaming teenage girls began banging on the windows," recalls Michele Priest, Shortland Street's head of assistant directors. "It was unlike anything anyone had ever seen in New Zealand. He handled it incredibly well, but it was surreal seeing him mobbed. It was then that many of us knew he was set for very big things."
It wasn't just his star power that was evident in the early days.
Longtime Shortland Street actor Michael Galvin (Chris Warner) recalls being captivated by his co-star's talent. "I remember watching early episodes to critique my performance and being completely preoccupied by Martin's scenes. Given how self-absorbed actors are meant to be, the fact that I was distracted from watching my work by a teenager's performance made me realise he had something special in terms of talent."
After three years, Henderson headed to Australia, where he starred on Home and Away and Sweat, befriending co-star Heath Ledger who would later join him in Sydney before the pair tackled Hollywood together.
Henderson went via New York, studying at The Neighborhood Playhouse School of the Theatre, then landing in LA.
His first year was gruelling. Friends were scarce, he felt like a "charity case" couch-surfing his way around town. He had to accept money from Ledger to survive and his professional life was a stream of rejection.
Countless times he questioned his talent and inched towards hopping on a plane home, where dad Ian lovingly reminded him he could continue acting with ease.
"All the rejection, heartache, disappointment and near-misses bring the inevitable questioning of, 'Why haven't I got a job yet? Maybe I'm only good in New Zealand?'
"Your self-doubt starts to erode your confidence, then you question your dreams. That's the hardest thing - finding self-belief in the face of all the rejection and holding on to what you know you're capable of.
"It's tricky because you don't want to get resentful and have a 'f*** you' attitude. The demands that puts on your personal development is the most challenging thing - finding the humility to go, 'I'm not going to take it personally,' then staying committed to doing classes, working hard and remembering why you're there."
Refusing to succumb to the Hollywood hurdles that frequently churn through actors and spit them back to their homelands, Henderson persevered and landed roles in The Ring, Torque, Bride and Prejudice and Britney Spears' saucy Toxic video.
Smokin' Aces, Little Fish and Battle in Seattle followed.
It was around this time that the demands of hopscotching between film sets started to weigh on Henderson and as he mulled over his future came the biggest jolt - the shattering news that Ledger had passed away, due to an accidental overdose.
Devastated, he left LA, unsure if he would return.
"There was a while after Heath passed away that I went home for a bit. I did a film in Sydney, a play in Melbourne, then a film in New Zealand, but I was just questioning it all because we came over here together and it was like, 'Yeah! Hollywood!'
"So after that I was like, 'Man, what's it all about?' I stepped back from my career and wasn't terribly interested in it.
"But eventually I started getting back on track with what I wanted - that aspiration I had from a young age. I always had that dream of, 'If I'm going to act, Hollywood is what I want to do,' so it was about honouring that and realising that to not commit and follow through would be betraying myself.
"And after that loss it was important to spend time back home. I love home and when I'm there I just feel good. I needed to reconnect and be around family."
Another knock summons Henderson to rehearsals, after which he's whisked to the Operating Room to practise his next surgical procedure, intense concentration sweeping over his face.
In between takes, the Grey's cast light up at mention of "McKiwi".
"He's a peach!" says Caterina Scorsone (Amelia Shepherd). "He's been a great addition to the show. So sweet and very generous."
It's not just on Grey's that Henderson quickly made his mark. Whether it's his third form French teacher Joan Farrell - who remembers him as "a focused, nice, well-balanced young man," - or his co-stars, the Kiwi charismatically leaves a trail of good impressions.
"He's just such a sweet man, really committed and always upbeat," says Everest's Jake Gyllenhaal. "Any time an actor talks about another actor I feel like I'm on The Howard Stern Show, going, 'He pisses lemonade and shits rainbows! He's the best!' But the thing is, I really do like him."
We meet again three days later at a French cafe in Miracle Mile. He arrives late, checks the time before deciding what strength coffee to order (a cortado), puts his phone in his pocket then chats away, graciously ignoring the fact he's 30 minutes behind for his next meeting.
Like his close friend Ledger, Henderson, too, could have once fallen prey to the dangerous side of showbiz.
He "loved alcohol a great deal ... too much" and, at 23, recalls a teacher he greatly respected declaring he had a beautiful life ahead if he worked hard ... and stopped drinking.
It wasn't the first time he'd been called out on his "excessive" boozing, but her words stuck and eventually, at 27, Henderson quit alcohol.
"I did party a bit when I first came to LA, which is its own trap. The celebrity and Hollywood culture is a whole world that becomes all-consuming. You see lots of people get here and think that's what it's all about.
"People think if you're at the right party or in the right circle that's an avenue to something, but I've never seen it as anything other than a distraction. I've consciously gone, 'I don't want anything to do with that.'
"I love my work, but I've always tried to keep my life similar to how it would be back home - sailing, hiking, cooking, my dog, my friends. This world is so abnormal that, in a way, it's not reality and it's important not to get caught up in it."
It's not just the partying and glamour of Tinseltown that Henderson has actively avoided, but fame in general.
He would rather be biking the Santa Monica mountains than cruising red carpets and he's more often found surfing in Malibu than posting selfies on Instagram.
If his media presence has been intensified by Grey's, he's unfazed.
"I experienced fame, albeit on a smaller scale, in New Zealand when I was still forming my identity. I was 17, on magazine covers and people would write stuff about me. I felt pressure to embody what others were thinking and after a while that felt unsustainable and unhealthy.
"I felt that part of it was bullshit - the celebrity culture. People love to read about who's hooking up with who and a lot of the time it's nonsense.
"By the time I moved to America I knew I didn't want to get embroiled in all that, because then you're living through other people's eyes. When you have fame, people drag you down and think you're shit or build you up and think you're incredible and the truth is neither, so I don't ever want to get invested in anyone else's opinion."
It's curiously ironic that perhaps the least fame-hungry Kiwi actor in Hollywood has found himself in the most memorable tabloid headlines.
In 2004 it was him getting hot and heavy with Britney Spears, recently it was reported he was consoling Jennifer Garner following her marriage split and who can forget that time he was splashed across global media labelled as Demi Moore's "new, younger man"?
"Someone sent me an email with an article when we were photographed leaving a general store in Connecticut with some cheese that we were taking back to a friend's house for lunch," he recalls. "I was like, 'Oh God, I can see how this is going to become someone else's idea of something.'
"But I didn't see another image. I would hear snippets of people's opinions, but I never read anything or saw an image and that's what I mean about not wanting to get invested in other people's take on stuff. I never want to be influenced by someone's opinion, positive or negative."
So, did he date her?
"Demi? No, no, no! But what happens is you deny it and they go, 'Martin insists they're just friends,' and that becomes fuel to create speculation that it's now a clandestine relationship. Now it's a story that we're sneaking around.
"So if I say 'Yes,' I confirm a lie and if I say 'No,' it creates a lie as well."
He shrugs off whether such experiences make him more wary of who he's seen out-and-about with, or if his awareness of public attention was heightened while filming Miracles From Heaven with Garner.
"I just live my life. Jennifer and I hung out a bit and I think someone saw us at dinner and there was a thing about, 'They're having dinner!'
"But I made a conscious effort not to read anything because there was a huge amount of tabloid energy circling around her relationship with Ben [Affleck] and I didn't want to bring that into my working relationship with her."
Contrary to those romantic headlines, Henderson is single. He'd love to get married and become a father, having been smitten with his Miracles From Heaven daughters, and he is the proud uncle of three nephews, the eldest of whom he's just enjoyed introducing to Disneyland.
However, he's wary of pinning his future hopes on parenthood. "I've always wanted kids, but I never felt ready. I wasn't mature enough to have them earlier. It would've felt more of a burden, whereas today I'm at an age where spending time with kids or my nephews is wonderful.
"But I'm not going to rush out and do it for the sake of it. I don't think having a family is the answer to anything, but more a complement to life. I'd rather find the right woman first, but life's funny - I might find someone and they can't have kids.
"So I don't want to get hung up on the idea because then if I met someone who couldn't, I'd feel like I was being denied something."
In a town where headlines centre on the latest showbiz break-ups, Henderson's also cautious of the type of woman he will consider dating.
Right now, that means no actresses.
"There's an actress I was keen on," he shares. "But do you really want to marry someone who's doing the exact same thing you do?
"If you marry someone and love them, you support whatever they want to do with their life. That means I would have a vested interest in having my wife constantly leave me.
"I don't want to be questioning whether I want my wife to be successful. That stuff comes up so often when two actors are married. You get professional jealousies or insecurities unless you're both working, but if you're both working you're not going to see each other and the relationship will struggle, then if you throw kids into that...
"I'm not saying I won't ever marry an actress, but in this case I did go, 'I'm not going to date that girl because ultimately that's not what I want.' I think you have to broaden your sights and cast a wide net for women from all walks of life and continents."
In the meantime, he's the "happiest I've ever been" and relishing a job that allows him to go home every night, but still grants the opportunity to make films in his hiatus.
He misses New Zealand deeply, but heads back frequently, cherishing every moment, "even if my sister and I are fighting constantly, like we have since we were kids".
And while farewelling family leaves him "slightly depressed" during his first week back Stateside, his Kiwi ties remain strong, hanging with fellow acting expats like Kieren Hutchison and Cliff Curtis, watching every All Blacks game, helping other Kiwi actors transition to LA - and once moving into a house because it had a feijoa tree.
"I love America and I'm grateful for everything it's given me. I love my life and friends here and I'm making a really good home.
"But nothing beats that feeling when I'm home - whether it's turning on the news or a talk show and going, 'Yeah ... there's my people.'
"The smell of the New Zealand bush and the sound of the Waitakeres - it's in my blood and that connection is something I will always have because I need it. I need it in a sense of, that's when I feel like who I really am."
The latest season of Grey's Anatomy is currently showing on TVNZ OnDemand and will also air on TV2 later this year.