Olivia-Newton John when she performed at the Mission Estate Winery Concert in Napier. Photo/ file.
Olivia Newton-John is telling me why she was going to turn down Grease.
"There were a couple of reasons why I didn't want to do it," explains the 71-year-old.
"I'd just made a movie that was a total disaster, and didn't want to jeopardise a musical career that was taking off by making another bad film. Oh, and I was worried that I was too old."
Throwing back her tousled blonde head, the Australian actress bursts out laughing.
"I was 29 - and convinced I was way too old to be playing a 17-year-old. Of course, now I look back and think, 'What was I worried about?' "
Joyous incredulity seems to be Newton-John's default emotion today. Which makes sense.
After all, we're sitting in Julien's Auction House, Beverly Hills, surrounded by more than 40 years' worth of the star's memorabilia.
In pride of place is the black leather jacket and skin-tight trouser combo from Grease's closing scene (expected to fetch US$200,000) and, to our left, Sandy's Pink Ladies jacket.
There's the custom-made Fifties lace gown she wore to the 1978 premiere of Grease in Los Angeles, costumes from Newton-John's cult-classic Xanadu, her Physical tour dress and a wall of music awards collected by the four-time Grammy award-winning singer over the years.
If all that weren't enough to feel joyously incredulous about, there's the memory of her old friend John Travolta "coming to see me and convincing me to do it [Grease] - because I honestly didn't think I was going to. And when I asked for a screen test to see if we had the chemistry needed, that test cemented it."
A gurgle of laughter starts up again, "because we did have it. Lots of it."
The Cambridge-born daughter of an MI6 officer who worked at Bletchley Park still can't quite believe that Randal Kleiser's raunchy teen homage to the Fifties went on to take US$400 million at the box office, making it one of the highest-grossing musical films of all time - and Newton-John an overnight global sensation.
Or that the gaggle of cross-generational cameraphone-wielding fans assembled outside the auction house now are trying to get a shot of her.
But, perhaps most of all, Newton-John is joyous and incredulous that she's here now, "and doing great", despite the stage 4 breast cancer diagnosis she was given in May 2017, when the illness she started battling in 1992 was revealed to have metastasised to her sacrum.
"I don't like that word 'battling'," she frowns - a slender, ageless figure in a black leather jacket, with the same sweet, high-cheekboned face the world fell in love with 41 years ago.
"I've never seen cancer as a fight or a battle. In fact, over the decades I've kind of befriended it - and right now I'm asking it to leave. Because instead of picking a fight with my body, I would rather keep calm and thank it for everything it has done for me."
She shakes her head. "I'm sure that sounds strange to someone who isn't in my position. But I've had this since 1992, on and off, and been through all these different stages. I've been vegan and macrobiotic and I went for many months without sugar..."
But a lot of those things felt like punishments? "Yes! And I'm not saying they don't work, but everybody has to choose their own path."
The Olivia Newton-John Cancer Wellness & Research Centre she founded in Melbourne in 2008 explores every one of those paths, from wellness programmes to breakthrough therapies.
But in terms of pain relief, one thing has worked above all else for Newton-John, and that's medicinal marijuana. Were it not for the tincture that John Easterling, her herbalist husband of 11 years, makes for her, the actress would have found it impossible to wean herself off the morphine she was forced to take when she fractured her sacrum.
"And it was hard. But the tinctures really help. Nobody has ever died of cannabis, but opiates are killing people every day."
Then there's the attitude she has chosen to adopt in so many areas of her life, despite having experienced more than her fair share of hardship and grief: the loss of her elder sister, Rona, from a brain tumour; and the disappearance of long-term cameraman boyfriend Patrick McDermott, who vanished on a fishing trip off the Californian coast in 2005 - and whom investigators have since alleged isn't dead, but alive, well and living in Mexico.
"Right now, I do things that give me pleasure and joy," she shrugs. "I eat healthily, but if I want a piece of chocolate or a cookie, I'll have one - because it makes me happy. Have you read that wonderful book, Spark Joy, by Marie Kondo?" she asks of the bestselling decluttering bible.
"You could extend it to all of life, really. These things brought me joy," she says, gesturing to the 500-odd pieces of history surrounding her, "but I'm letting them go. I can't take them with me, and my daughter is not going to want all this."
Growing up in her mother's shadow hasn't been easy for 33-year-old Chloe Rose Lattanzi - Newton-John's only child from her first marriage to actor Matt Lattanzi. And the actress and singer, who had a hit with You Have to Believe, which she co-wrote with her mother in 2016 - has spoken out about the deep-seated issues she has suffered over the years: the anorexia, depression and substance abuse that sent her into a self-destructive spiral in her twenties.
"Fame messes you up," she told one interviewer in 2013. Newton-John is the first to acknowledge how hard it must have been for her daughter.
"Having a mother who is famous, and having this image that nothing goes wrong [for them], but also feeling you're having to share them with the rest of the world... that must have been tough. And the teenage years were not easy," she adds.
"But now Chloe's got me to herself - and we're very close. Actually, I think this," she says, not willing to give her diagnosis the weight of its name, "has brought us even closer together."
Having her daughter looking after her for months at a time "was a really bonding experience", says Newton-John.
"She's really maturing and realising that I can be vulnerable, too. And the other day, she said to me, 'Mum, I had my own form of cancer, so we can heal together.' Which I thought was really beautiful. But she's on top of things, and I'm so proud of her."
Like every mother, Newton-John obsesses over the choices she made. The fame might have been beyond her control, but she often wonders whether her decision not to tell her six-year-old about the original breast cancer diagnosis in 1992 was the right one.
"Chloe's little friend Colette had died the year before of kidney cancer, and we were all still in shock about that when I got my diagnosis. Looking back, I wish I had told her, because when she found out about it from her friend at school, she came to me, saying, 'Mummy, you should have told me - I would have taken care of you'."
Newton-John closes her eyes at the poignancy of the memory. "But you make your decisions, at the time I thought it was the right one, and what matters now is that Chloe looks to me more and more for advice. And I'm so happy to give it to her."
Knowing what you would and wouldn't be prepared to do for the sake of your career is something Newton-John has always urged her daughter to keep in mind. "As a woman, we've all had issues on sets..." she starts.
MeToo issues? "Well, I don't want to go there," she warns. "But it is so difficult being a young actress and starting out in this business, because it's all about boundaries and knowing what those are."
She pauses.
"The casting couch thing was real in my life, too. I never really had it done that heavily, because I think I always managed to make light of things and let it go - but also I would never put myself in certain positions. That disastrous movie I had done just before Grease," she goes on, "it was called Tomorrow, and shot in Pinewood Studios. I was there when the director said, 'There's a scene in the movie when you go up into space and your clothes come off and you're just going to be in a bra and panties.' And I said, 'I'm sorry, I can't do that.' My career was important to me, but so were my boundaries."
It's a Sandy With Her Inner Steel-like sentiment, and although I know that our time is up, and the chants of "ONJ!" are growing more insistent outside, I'm curious to know one thing: when was the last time she watched Grease?
"That I can tell you," she grins, explaining that it was a little under a decade ago, when Travolta - who has remained a close friend - invited Newton-John and her husband to dine with him at his house in Florida, and to see his newly refurbished plane while they were there.
"Somehow, in conversation, it emerged that my John had never seen Grease." What? "Well, he'd been working in the Amazon, so it wasn't really in his realm of consciousness. But John couldn't believe it. So he took us on to his plane, and he had set up Grease to be playing," she laughs.
"John watched it from beginning to end, and when the credits rolled, he turned to me and said, 'You know what? That's a really good movie...' "
Film distributor A24 used this to promote Celine Song's 'Materialists'.