Kate Winslet, dazzling in her new film, tells David Gritten about the even greater adventure she faces - having a baby

KATE WINSLET has a contented, relaxed look these days. In the past I have seen her looking tired and tense as she struggled to maintain her rigorous filming schedule. On one occasion, we met just after she finished shooting Titanic, when she was angry at director James Cameron's tyrannical excesses.

It's amazing what marriage and pregnancy can do. Eighteen months after she married film-maker Jim Threapleton, her sense of familial bliss seems undimmed, and she is happily expecting a baby later this year.

Winslet has been meaning to ring me for the last three days, but it has simply slipped her mind. "This has turned me into the most crap person in the world," she tells me good-naturedly. "I didn't know a symptom of early pregnancy was absent-mindedness. But it's true in my case, and it's been true with friends of mine too.

"I'm feeling a bit nauseous in the mornings, but honestly we're so thrilled," she goes on, her words spilling out with her enthusiasm. "And it's such an important thing - the most wonderful thing two people can do together. When it happens, it happens, and everything else has to fit in around it, not the other way round."

Indeed. Quite apart from these happy events, Winslet now looks like a young woman in control of her destiny, someone who calls the shots. Before Titanic she was an actress in a hurry, eager to stake a claim for herself and throwing herself into continuous work - Heavenly Creatures, Sense and Sensibility, Jude, Hamlet. One sensed she was being run by her career.

Then Titanic, the highest-grossing film ever, made her the world's most visible young actress. She could do whatever she wanted. Hollywood studios brandished fat cheques and jostled to sign her up. "I was offered everything under the sun," she says, with a wry smile.

And what did she do? Something very sane. Staying away from Hollywood, she made two quirky, independent, modestly budgeted films: one, Hideous Kinky, in Morocco; the other, Holy Smoke, in Australia and India. "After Titanic I made a decision to do something smaller," she explains. "I needed to remind myself I was doing this job for a reason - because I love it. I could have done a lot of big films, raked in the cash and forgotten that it's not about being a film star, but trying to do good work."

Success has not changed Winslet. She retains her common sense, effervescence and stubborn streak. She chatters incessantly, swears with confidence and laughs like a drain. She's a good egg and a terrific role model for a generation of British women.

Although she has received two Oscar nominations (for Sense and Sensibility and Titanic) she is still only 24, and it says much for her grounded world-view that she retreated from the public eye in the wake of Titanic's huge success.

Her Moroccan film, Hideous Kinky, was amiable if hardly memorable (she herself calls it "a little road movie"), but it paid unexpected dividends: on set she met Threapleton, then an assistant director. She credits him with giving stability and direction to her life. "For me, Jim's the person who sees through all the bull**** and keeps you real. Those are things I've fought forfor myself, and to have found somebody else who does that with me, honestly, it's great."

Threapleton's career has now moved up a few notches. "He's not an AD at all any more," she Winslet reports. "He has directed a couple of short films, on a low-key level," Winslet says. "I'm not allowed to be in any of them, which drives me mad. But it all seems to be going well. Jim's just pleased he's not running around any more making cups of tea for people like me."

Winslet too moves into headier territory with her new film, Holy Smoke, released here on March 31. Directed by formidable New Zealander Jane Campion (The Piano), it offers Winslet the most complex role of her career. She plays Ruth, a headstrong, exasperating young Australian who takes the hippie trail to India and falls under the spell of a guru with a less than spiritual interest in his female devotees.

RUTH'S family hoodwink her into returning home, and hire an American cult deprogrammer called PJ Waters (played by Harvey Keitel) to sort her out. He drags her off to the Australian outback for an intense one-on-one session to reverse her brainwashing. Ruth seems insecure, while Waters boasts that he has returned 180 cult victims to normality, yet it is soon clear that she is more than his equal in sexual terms and in strength of character. They embark on a frenzied affair, and she undermines his arrogance at every turn.

Under a spell: Winslet as a victim of brainwashing in her new film, Holy Smoke, directed by Jane Campion

Holy Smoke has polarised opinion sharply. But even those critics who are uneasy about its inconsistent tone concede that Winslet has turned in the performance of her career.

However, the film proved too rich for the palates of Oscar and Golden Globes voters, who overlooked her. There were also signs that Miramax, the company that made Holy Smoke, distanced itself from it when it opened to indifferent business in America. Certainly the company has not marketed the film with its normal verve, and Campion has cancelled a publicity trip to Britain, apparently in despair.

"It's a brilliant story, and of all the films I've done it's the one I care about most," says Winslet defiantly. "It was a real challenge for me. It is by no means a masterpiece, but it's a really interesting movie. I've read articles about it and it sounds as if we've made this steamy, erotic film, but it's not that at all. It's about a young girl on a journey to find her heart."

The role of Ruth is arduous, physically and emotionally. Intriguingly Winslet found it hardest to play innocuous scenes with two of Ruth's young Australian girl-friends. "Those actresses were very girly," she says. "I was 22 when I shot the film, but I felt at least 25 - older, wiser. I thought, God, I don't know how to be young any more."

IN a sense she never did. Winslet, who comes from a theatrical family, has made a living from acting since the age of 13. She began work on BBC sitcom Get Back days after completing her GCSEs, and won her first Oscar nomination just after her 20th birthday.

"I've always said I've never missed being teenage and girly and silly," she says, "but when I did those scenes in Holy Smoke, I realised that I'd skipped that beat. I never did that going-out-to-clubs thing. I've always related to people 10 years older or more."

That category includes her friend Emma Thompson, who wrote and co-starred with Winslet in Sense and Sensibility, and Campion, with whom she bonded on set. "I used to get annoyed with Jane, who'd always be saying [adopts a Kiwi accent], 'We're all on an important part of our journey.' And I'd think, 'Shut up about the f***ing journey - I just want to get on with it.' But when I saw the film, she was right. It was an unbelievable journey.

"Playing Ruth was intense. Every day was the equivalent of doing a nude scene. As an actor I like being pushed to extreme places. Well, Jane will drag you there kicking and screaming."

Campion certainly needed to for one scene. Winslet has disrobed in most of her films with apparent unconcern, but one unsettling moment in Holy Smoke might have deterred the most confident actress. After a bruising encounter between Ruth and Waters, she stands naked before him in the desert's gathering gloom and urinates - a sign of the extent of her emotional breakdown and fatigue.

"I laughed my head off when I read the scene. Then I had to face the reality of doing it," she says. "We had this hilarious contraption, and lots of giggly girls in a toilet trying it out. There was a saline drip on my back with food colouring in it. I had to wedge a tube in the appropriate place and squeeze. I was helped by the content of the scene. If it was meant to be about seduction, it would have been harder."

As she tells it, she has virtually no inhibitions these days: "The experience of working with Jane altered my attitudes. I don't care any more. I think a lot of women don't get to that point until they've had a baby or reached their mid-thirties. I almost cringe when I mention this, but the topic of my weight - it doesn't bother me any more."

Ah yes, her weight. After Titanic she was judged harshly by more shrewish elements of the media for putting on a few pounds. Winslet is unforgiving and indignant.

"At first all that stuff was pretty hurtful. No one has the right to judge like that. Why slag off my physicality? Because actually I want that to be a good thing, I want it to help young people who are completely messed up. It breaks my heart - I get letters from mothers of young girls who were anorexic and no longer are, because they've read articles and things that I've said."

Winslet's pregnancy has made her delay making her debut as a film producer on Thérèse Raquin, an adaptation of the Zola novel, in which she also takes the title role. She was due to start filming in May, but will now begin it next year. She won't produce every film she makes from now on. "But I like to be hands-on, and I love that whole team thing, keeping the team happy."

The attachment of her name to a project has another advantage since these days Winslet is a money magnet. Once she commits to starring in a film, investors automatically start sniffing around. She did it with Hideous Kinky, she's doing it with Thérèse Raquin, and last year she added to the star lustre of Quills, a film about the last days of the Marquis de Sade, which pits her against Michael Caine, Geoffrey Rush and Joaquin Phoenix.

But next she will play a role in Enigma, a film adapted by Tom Stoppard from Robert Harris's novel about the Second World War code-breakers at Bletchley Park. The film's executive producer is none other than Mick Jagger, who impressed cast members by taking them up to Bletchley last week, and showing them around. He has real enthusiasm for the subject.

"I suppose I shouldn't say this," says Winslet, who goes on and says it anyway, "but when I heard about Mick, I thought, huh, wonder why he's so interested in producing films? But he was terrific. And he did something very sweet. He made up compilation CDs of 1940s music for all the cast, which really impressed me. That's just the kind of thing actors like as a way to think themselves into a period. And most executive producers, you think of them sitting in offices, taking money decisions. You don't expect them to be hands-on. So Mick impressed me."

In Enigma, she plays a key code-breaker called Hester: "I'll work for four weeks in April before I get too big." And then? "I'll be lying flat on my back," she says with a laugh. "Those people who slagged me off over my weight can have a real go at me then. I'm fully intending to blow up like a real barrage balloon."