From the mouth of one of its own, a trendy London is getting a kicking. "The Ivy restaurant?" says Kate Winslet, blue eyes blazing in a strong, creamy face. "I can't stand it. I've got a real thing about it, it's a celebrity hang-out and I cannot stand celebrity hang-outs. It's like my doctor said recently: 'Maybe you should think about where you'd like to have the baby', and I said: 'Not The Portland.' It's a celebrity baby factory (she giggles mischievously). I'm sorry, but it is."

And this is how Kate Winslet is. The mother-to-be may be the youngest actress to be twice nominated for an Oscar but she is also funny, irrepressible, down-to-earth and more than happy to talk about her life: "I'm not smoking now, of course, but I love a drink and I love a party, but with my mates and Jim's. I'm not one for hanging out at the Met Bar and being photographed coming out all skewy-eyed. I've never been one for drugs, they never came my way when I was a teenager and by the time they did, I'd grown up a bit too much." This is the way she talks, openly, unstoppably. It's often interpreted by interviewers as honesty and enthusiasm, and there is that too, but really (because no one is going to bare their soul in a 30-minute interview) Kate Winslet is a consummate and generous professional. She wants to give you something to take away. She is driven to give you her best.

Everyone identifies with Kate Winslet - or at least the characters she plays. The latest is Ruth, a headstrong young Australian, whom we see in the opening frames of Holy Smoke wearing a white sari having gone native in Delhi. Everyone wants to be like Kate Winslet because she's always diving in, looking for the real stuff, pushing at boundaries, whether as Marianne Dashwood, the passionate idealist in Sense And Sensibility or Sue Whitehead, the unmarried mother in Jude, the rebellious Rose in Titanic or the hippie mum in Hideous Kinky.

If you're an adult, you think that, at the very least, she's an impressive talent. If you're an adolescent girl, you think she is unbelievably cool (after all, she effs and blinds and has starred in the biggest- grossing movie of all time).

If you're female, over the age of 12 and not built like a scarecrow, then Winslet has made a crucial difference to your self-image, putting curves - at a glance, I'd say a size 12 on top, 14 on the bottom - back on the screen. And not only back on the screen but straight into the arms of Leonardo di Caprio no less. And if you're any of the above and British, you can't help but see her as a kind of walking advertisement for down-to-earth, get on and muck in British spirit. This is the woman, remember, who served bangers and mash at her wedding reception in the Crooked Billet pub in Reading and then honeymooned in Scotland in November. How's that for unponcey?

On our behalf, Kate Winslet has given two fingers to the skinny Gwynnies and moaning Winonas. Everything she does both in her work and private life is strong and beefy (she turned down the Gwynnie part in Shakespeare in Love on the grounds that it wasn't enough of "a stretch"). So it's astonishing to discover that the old Kate has been shed somewhere in the Australian desert and that, in fact, we ain't seen nothing yet.

Holy Smoke is the big one, not in terms of Oscars or even Golden Globes, (both of which seem scared off by the subject matter); but in the Kate Winslet oeuvre, it's the one that demonstrates her talent at its most fearless and mature. It's the story of Ruth, a woman who falls under the influence of a charismatic Indian guru, is lured home to be "deprogrammed" by a Cuban-heeled exit counsellor, played by Harvey Keitel, and the complex struggle that ensues between his smooth, professional expertise versus her lack of inhibition and self-confidence. Keitel's strong performance, even the moments when he's trussed up in a dress pleading for sexual favours (Winslet: "So what are you?" Keitel: "A dirty old man"), is eclipsed by hers. There's a point where she stands naked in the desert and urinates involuntarily on the sand between her legs. You can't imagine anyone else having pulled it off. Was anyone else considered for the part? "Yeah, I heard that Jane [Campion] met 600 people," says Winslet, and laughs.

Everything up until now has been, she says, mere training for the ordeal that was Holy Smoke. "Acting is about taking risks and this was just so risky." The intimacy of the scenes was "really difficult. It was like 'Woah, hang on a minute'." But nothing compared to the arduous mental preparation. "Jane is pretty brutal. She'll come up to you and say [switching into a languid Australian accent]: 'Er, Kate, that was really baaaad.' She makes you explore sides of yourself and sometimes you don't like to have to admit certain things. She'd say: 'You have a real thing about people liking you, don't you?', and I'd say: 'Well, not really ... but on the other hand', and she'd say: 'Make up your mind, you're contradicting yourself.' She demands total honesty." The liking thing is interesting. Winslet has a reputation for team-spiritedness, for being best friends with the make-up girl and the props boys and she's keen to demonstrate her normality ("I'm dying for a pee" is the first thing I hear her say). She was bullied at school in her teens for being overweight and you can't help but connect this with her subsequent unwavering determination to be the most popular, in-demand, actress of her generation.

Along the way she has acquired a reputation for becoming intensely, even dangerously, involved in her parts. "I'm always fainting and going to hospital, honestly." She collapsed on the set of Sense And Sensibility. So was that corsets or emotion? "Corsets, emotion and rain," she replies.

But it was during the making of her first feature, Heavenly Creatures, that her sanity was most at risk.

"I came home from that film and I had no idea who I was and I was really frightened. It taught me to protect myself and with Holy Smoke I had to apply those lessons," she says.

When she finally saw the end product she was shocked at what she had created. "It had taken on this bigger life and I just thought, that is not me at all. I was like, 'Who the hell are you?'"

She says she doesn't recognise herself but the characterisation feels very like the Kate Winslet we all think we know. "Well, I really enjoyed being Ruth. I loved the costumes [saris and hippie gear] and running around with no shoes on. That's completely me. And a lot of Ruth's mor- als, sticking up for what you believe in and being honest and headstrong, that's very much me.

"Playing her I realised that she was a lot younger mentally. I had to take myself right back [Ruth is about 20, Winslet was 23 at the time of filming]. When I was 20 I thought: 'Yeah, I know exactly who I am. I absolutely know what I want from my life.' Cut to me four years later and I am a drastically different person."

It's probably hard for Winslet to appreciate that most of us had little idea of who we were at 20, or were anything like as self-assured at 24, let alone so far into a career (besides starring in the film of Robert Harris's Enigma and another film about the Marquis de Sade, she will co-produce on her next project, the film of Therese Raquin). By her own admission she was an early starter, sorting out her own affairs, looking after her work interests in order to "protect" her parents. She made her first film at 17 and at 19 she was nominated for her first Oscar for Sense And Sensibility. The same year she was on the phone to James Cameron lobbying for a part in Titanic. Is it true that she shouted "I am Rose" down the phone at him until he relented?

"Not quite. But I did phone him up and I said [serious nanny voice]: 'Look, you really do need to cast me in this role', and he laughed and I said: 'Laugh all you like but if you don't, you're going to regret it.' Actually I was the first person they cast which, looking back on it, was bloody brave of them."

The finger episode, when Rose makes a decidedly late 20th century gesture as she escapes in the lift, was presumably a bit of ballsy Winsletian improvisation? "That was actually Jim Cameron's idea, which we had a row about - I said it feels too contemporary."

It's the old overlap again, assuming that Kate is this gutsy force who refuses to conform to type. "That is pretty true of me, actually. Jim [Threapleton, her husband] was saying the other day: 'You know you should really treat yourself to something', because I'm not very good at saying 'Well, I've got a bit of money now, so I'll buy myself something nice'. That said she has recently bought her parents something nice - a house.

"He said: 'Maybe we should get you a little sports car' and I went 'Eyuuurk!'." She lurches forward tongue out, eyes bulging. "He said: 'You know you are allowed to have some of the superstar things' and I said: 'No I'm not, you see, because I refuse to do what people expect me to do. That's very much who I am, so I'm much happier driving around in our little green Mini, thank you.'"

She married Threapleton, whom she met when he was third assistant director on Hideous Kinky, four months after filming Holy Smoke. There's no doubt that it is her coming-of-age film because she carries through it a luminous beauty. The slightly whiney girlishness that sometimes surfaced unintentionally has been replaced by a confident womanliness, and for the first time you are aware of her extraordinary sexual power.

"Well, I like that," she beams. "That's really good. I am very in touch with who I am and I think that, without wanting to sound mushy, that is to do with being married and being with Jim, because there's no one out there to question me any more. He just loves me for me and vice versa and that is really grounding." So does she feel that Holy Smoke was like a rite of passage?

"Yeah. When it was over, I had this overwhelming feeling of 'Oh my God, I've just closed a chapter of my life'. It felt like I was exorcising sides of myself."

Maybe some of those demons were to do with her much-discussed body image: at the age of 16 she was 13 stone, then she became dangerously thin, and ever since her figure has been the subject of intense press scrutiny. Did she love the way she looked, naked in the desert?

"I have to say I was quite chuffed because it was a bloody hard scene to do and I was racked with paranoia as I always am with every nude scene. Not that I wasn't eating several packets of crisps before that scene. But yes, I was pleased."

Now she says she can't wait to get a proper bump to show off. But she's not ready to stay at home with the family yet. "My feeling about why I like making films is you can come away from a film feeling so changed and touched. I really love that, the thought that I could be giving people a lot"

Source: The Sunday Herald Magazine