"People say to me, 'You seem to have made this conscious decision to do independent films'," offers Kate Winslet. "In reality, I haven't. After each movie, I always think, how different can I possibly be?... Is this going to challenge me, is this going to inspire me, and is this going to make me love my job more than I already do?"

Staying true to her ambition has involved turning down high-profile parts including Gwyneth Paltrow's role in Shakespeare In Love and Jodie Foster's title role in Anna And The King. For her, those parts were "predictable" – something the British actress is anything but.

Kate was born on October 5, 1975, in Reading, England, to a family of thespians. Her grandparents founded the Reading Repertory Theatre and her parents, Roger and Sally, were both stage actors. Kate attended theatre school in Maidenhead and made her acting debut opposite the Honey Monster in a Sugar Puffs advert. But loftier fare was waiting in the wings. She made her first stage appearance aged 13, and just four years later burst onto the scene as a homicidal teen in Heavenly Creatures. An Oscar nominated turn in Sense And Sensibility followed, before she made waves in James Cameron's Titanic.

"Never did I think Titanic would be so big," she says a bit naively. The film went on to gross upwards of $1 billion worldwide and Kate "was offered everything under the sun". Rather than cash in on her new-found fame, she set off for Morocco to play a woman in search of her heart in the little-seen 1998 work Hideous Kinky. "It's not about being a film star, but trying to do good work," she says.

The youngest person ever to be nominated for two Academy Awards, Kate found much more than "good work" on the North African set. "I arrived and saw this rather glorious-looking blond boy with fantastic blue eyes," she says of meeting Jim Threapleton, the film's third assistant director. "I just went, 'shit', because I knew that was it and there was nothing either of us could do about it." The two married in November 1998 in a low-key ceremony at her local church in Reading, and daughter Mia followed nearly two years later.

After giving birth, Kate struggled to regain her famously curvaceous figure. "People tell you the weight drops off afterwards. Hell-o! It does not," she said. And while she later lost four stone, she remains a role model for women who enjoy a hearty meal. "I used to be so hung up about it," admits Kate, who was dubbed "Blubber" as a teenager. "I finally realised I was spending about 90 per cent of my day thinking about my body, and I thought, 'This is just so boring!'."

Kate and Jim seemed the picture of happiness for three years, often photographed about London with baby Mia in tow. However, in August 2001 the couple decided to call it quits. The actress subsequently married American Beauty director Sam Mendes in May 2003, and welcomed her first child with her new husband, a son named Joe, in December of that year.

As Kate's career goes from strength to strength - her latest Oscar nomination came for her role as a youthful Iris Murdoch in 2002's Iris - it seems the actress is still learning about herself. "When I was 20 I thought: 'Yeah, I know exactly who I am. I absolutely know what I want from my life'," she says. "Cut to me four years later and I am a drastically different person."