Katy Perry is in love.

She's in love with life and her little cat, who just happens to be sitting beside her eating a bowl of sugar - of all things - when the singer talks to TimeOut from New York. But most of all she's in love with her fiance, Russell Brand, the British comedian, actor, former sex fiend and bad boy whom she met after throwing a bottle of water at him at the MTV Music Awards.

Though she doesn't go into specifics about her man on new album, Teenage Dream, which is out on Monday, he is the inspiration behind the strong theme of L-O-V-E (love) on songs like Not Like the Movies (about the crazy notion of actually finding someone who is perfect for you) and Hummingbird Heartbeat (with the opening line, "You make me feel like I'm losing my virginity").

"There are a few different songs that are influenced by love. That's a subject that's invading my hemisphere right now," she laughs, "which is exciting because the last record, One of the Boys, didn't really have much of that."

The 25-year-old, who had a Christian upbringing in California before venturing to Nashville, Tennessee, aged 15 to hone her songwriting skills, released a self-titled gospel record in 2001. Seven years later, after a considerable change of tack with singles like Ur So Gay and breakthrough single I Kissed a Girl, Perry hit the big time.

These days she's a woman in demand - and it's taken nearly two weeks to get her on the phone. But after two false starts - the first interview fell over because she had to run to catch a plane to Tokyo, the second because she collapsed of exhaustion on the promo trail - she's on the phone, sounding chirpy.

Are you over talking to random people from around the world about your new album yet?

[Laughs] No. No. Although I have been up since 4.30 this morning [it's now 2.40pm her time].

It's a great record. Yourself and someone like Rihanna make pop music a better place.

Oh yeah, I love that pop girl raising the bar thing that's going on these days. Taking it to the next level.

On the album, and especially the song Teenage Dream, there is a preoccupation with childhood, growing up, and those formative years. Why that trip back to that time?

I think there are a couple of things people think about or feel when they see the words "teenage dream" together. A lot of people fall in love for the first time and it's so intense and overwhelming, and lovely in a way, but it's so emotional. But when you're an adult you may not feel that way again. And then someone walks into your life who makes you feel that googly kind of love again.

That's what the song is about, and why I named the record that is because, in a way, I want people to fall in love with the record, and have that all-or-nothing feeling like a teenager.

There's a line in Teenage Dream that goes: "Let's go all the way tonight, no regrets, just love". Is it fair to say that that says a lot about you as a person: slightly naughty, but wholesome as well?

I'm definitely not the girl next door, although I am in a way, but probably more the girl who creeps into your window. I am a girl who takes the art of the tease to its limits and I enjoy walking that tight-rope line. When I was learning how to write songs someone taught me how important it was to give different meanings, use puns and double entendres, and if you give all that and more in your storytelling your song will be worth more.

So who was that person who taught you how to write songs? Was it from your time in Nashville?

It was a few different people and it was during my days in Nashville, Tennessee, when I was really getting into playing the guitar [aged 15]. There's such a country music storytelling scene there - and they really get emotional with their songs and I love that.

On the flipside, what do you learn and take from a bloke like Snoop Dogg [who features on the single, California Gurls]? He's been around.

When someone like that enters your world you kind of want to let them do the talking because they've got a lot to say. But he's just easygoing. I like him, and before he came into the studio to get on the song I was really excited about him, and I almost kind of pay him a little tribute in the lyrics of the song, hoping that it would be flattering so that he would want to be part of it.

But I'm telling you he was so chill, because sometimes you expect people to be uptight divas after so many years.

I'm sure you were never a bad person to start with, but how does your main man Russell make you a better person?

I think there is something to be said for finding your mate who makes you a better individual, and is a support to you. But generally he is just like my partner in crime in some ways because we've both got a wicked sense of humour. We're always pulling pranks on each other.

The other day he Tweeted a picture of my foot in my shoe and he pulled my pinky toe out so it looked like I had six toes. It's harmless fun.

And I made up a rumour that he was [being a] bridezilla which was really cool because that hit [headlines] all over the world.

And you know, life is too stressful to not have a laugh about stuff and it really helps. And it definitely connects you.

What do you hope for Teenage Dream then?

I think this second record will speak for itself, and it's more important even than the first record because it shows that either you're meant to be here or that it was a lottery or it was luck. And that will be up to the people, but I'm feeling really encouraged because it's nice to hear that in New Zealand and Australia a song like California Gurls reached No. 1 and it's not even summer time. I'm like, "Oh, great, it's not just a summer song".