Every actor needs a good entrance. On a chill winter's afternoon, Rachel Weisz provides a mini masterclass: the door to her London hotel suite swings open and in walks Weisz (you pronounce it "Vice") wearing naught but jeans, sports bra and an abundance of black eye-liner.
The actress, it transpires, has just completed a photo shoot and wants to make a private call. Mundanity replaces the sheen of celebrity. Later Weisz insists, "I'm not a celebrity, I'm an actor." There were times when the world must have wondered.
In career terms, Weisz has led a fairytale existence. Born to a creative, middleclass family of Hungarian emigres (mum a therapist, dad an inventor), she began modelling aged 13, turned down a role in Richard Gere's King David at 14, and took her own theatre company to the Edinburgh festival after graduating from Cambridge University.
She made her film debut as an "evil sexy bitch" in Bernardo Bertolucci's Stealing Beauty, smouldered darkly as the object of desire in Michael Winterbottom's I Want You ("my favourite piece of work") and popped up as the intrepid librarian in the hit comic-book horror romp The Mummy.
In the meantime - running as a gaudy sideshow - went all the other stuff. In the past five years, Weisz's raven-headed good looks have made her a darling of the glossies, while a series of famous boyfriends (director Sam Mendes among them) guaranteed her a high-profile slot on the showbiz circuit. But for a few different turns, she might be in Liz Hurley-land by now.
Weisz has taxied from her London flat to promote Beautiful Creatures, an offbeat (and ultimately off-target) comedy thriller in which she stars as Petula, a brutalised trophy girlfriend turned wised-up agent of vengeance.
Weisz plays Petula as a kind of social-realist Marilyn Monroe, a peroxide bombshell tottering precariously in high heels and arse-hugging skirts. "Petula is almost like the mythical blonde," she points out. "Technically, she was a real challenge to play."
On screen, Weisz can exude an exaggerated, vampish beauty. In person she's smaller, slighter than you'd expect, as though her image were the result of some chemical reaction between her face and the movie camera. Weisz maintains that she is never recognised in public, and this is how she likes it.
"James Dean or Elvis were celebrities, but it's so not a part of my life. People want to imagine I spend every night going to premieres and putting on frocks and getting into limos, and yet I do that maybe twice a year, if that. I think you have a choice, actually, and I've chosen to stay on the outskirts of that world."
Still, there have been times when she looked in danger of being sucked in - particularly when her relationship with British actor Neil Morrissey, the Men Behaving Badly star, dragged her briefly into the tabloids' orbit. Weisz shrugs: "Yes, Neil had embraced tabloid culture, if you can call it that. He was quite comfortable with it all." Not her? "No. I didn't like it at all."
Some actors play the shy-and-retiring card with a phoney flourish; others with genuine heart. With Weisz it seems more complicated than that. Previous interviewers have speculated that her career has been typified by a constant struggle to reconcile conflicting parental influences. On the one hand, they claim, Weisz is governed by her mother, who nudged her into modelling and lobbied hard for her to take the role in King David. On the other, she's intent on impressing her sterner, more purist father ("a really harsh critic - he didn't think I should be acting, because he thought I wasn't good enough").
Weisz is resistant to such amateur head-shrinking. Even so, she admits to feeling a strong degree of ambivalence about her gilded career. "It makes me uncomfortable," she says. "But I think I have a natural inclination towards guilt."
What does she feel guilty about? She draws on her cigarette and pauses for the longest time. "Sometimes, it all feels a bit too much that everything just seems to work out," she says quietly. "That you're attractive and successful and you've got a good education, and that journalists want to ask you all about it. I'm not confident around compliments or being celebrated, and I'm not comfortable with the thought of envy, which some people thrive on. Some people like having eyes upon them and I don't."
She gives an apologetic half-smile: "I know that sounds odd, because I'm an actor. But an actor is about being somebody else."
That said, her chameleon stance stops short of complete reinvention. In setting out on her chosen career, Weisz made one minor but crucial statement by hanging on to her surname. If not unique, she is certainly rare among Jewish actresses for not trying to "Waspify" her identity.
Weisz says that this only occurred to her recently. The more she thinks about it, the more interesting the whole thing becomes. "You have to wonder: would Winona Ryder be Winona Ryder if she was still called Nonni Horowitz? Or Lauren Bacall if she was Betty Perske? I don't know. What do you think? Does Weisz sound very Jewish?"
Well, yeah. She considers this for a bit. "Actually, I did want to change my name when I started acting, but only because I got so bored of people mispronouncing it as `Wheeze' or `Wize'. I wanted to change the spelling to `Vyce'. I couldn't do `Vice' or I would have sounded like a porn star. But my agent at the time wouldn't have it. He said, `It looks like a fucking number plate! You are not changing your fucking name.' But he's Jewish, so maybe that's why he did it."
In the event, the decision worked out fine: "I haven't only been offered Hasidic roles." In the past 18 months, Weisz has starred in Beautiful Creatures, filmed the sequel to The Mummy, played Ralph Fiennes's adulterous love interest in Istvan Szabo's undervalued family saga Sunshine and co-starred opposite Fiennes Jr (Joseph) in the Stalingrad siege drama Enemy at the Gates.
She also found time to appear on stage in an acclaimed production of Tennessee Williams's Suddenly Last Summer. It was, she says, the first time her father complimented her on a performance.
In March, she'll turn 30. "Your 20s," she sighs, "are a very difficult time." Mention that her 20s have seemed peculiarly blessed, and Weisz responds with an indulgent smile. "Ah, but you're talking about my career and I'm talking about my life. No - my 20s were horrible. I felt I didn't know anything. I was petrified and insecure and worried about everything. I think that as you get older you learn to let go of a few things. You come to know your own mind, values and morality. I used to be very driven. I'm feeling a lot less driven."
When the dust has settled, Weisz wants to take on another stage role, and direct a documentary. For the time being, however, she describes herself as "at the end of something and the start of nothing". It seems as good a starting point as any.
Beautiful Creatures opens Friday, January 19th