Sienna Guillory: Beauty and the beasts

She's strikingly beautiful, remarkably talented and a step from stardom. But Guillory hates acting. Nick Hasted hears why

Sienna Guillory is one step away from massive stardom. She made her name as sweet Northern beauty Jenny in the Kingsley Amis mini-series Take A Girl Like You (2000), served her apprenticeship in Brit B-pictures such as the dodgy drug movie Sorted (2000), and cameoed in major releases like Love Actually. Soon she'll be sprinting through Resident Evil: Apocalypse with Milla Jovovich, swinging a gun and wearing lycra. She's been a top model too, and was voted Britain's Most Eligible Woman in Esquire, before she married the actor-director Enzo Cilente.

All of which doesn't sound too different from the experience of any other young British actress on the rise. But in her new film, The Principles of Lust, Guillory, 28, shows she can be remarkable. It's a raw debut from the writer-director Penny Woolcock, about a young man (Alec Newman) pulled towards wild irresponsibility with a demonic free spirit (Marc Warren), when his lusty relationship with single mother Juliette (Guillory) starts to cool. Full of physical and sexual heat and emotional nakedness almost unknown in a British film, written and shot on instinct, Guillory throws herself into its extremes - lost in wild sex one minute, holding everyone together the next.

Meeting her in a north London pub, Guillory in person is still more shockingly fascinating, the unguarded, free-associating opposite of any clichéd Brit-babe. The daughter of the late Cuban guitarist, Isaac Guillory, a left-wing free spirit, she grew up around entertainers but, it's soon apparent, finds acting a bitter disappointment. Ruthlessly honest and self-excoriating, a fidgeting time-bomb of frustration and nervous energy, she pours out her soul almost unbidden. Her fearless self-exposure as she talks begins with what went wrong on The Principles of Lust.

"We were all in awe of Penny," she recalls. "You feel so safe with her, you end up doing things that might seem offensive to other people. It's almost like being in a therapy session. You go a little bit further than you would normally. But in the orgy scene, where Marc's really getting a blowjob, I was like, 'You've crossed the line!' Me and Alec were acting, and being loving and safe and showing the feeling of wanting to climb under someone's skin. For it to suddenly become something purely physical - I didn't think that needed to be real. But it was a situation that got out of hand. They filmed it at a swingers' club. There wasn't any way of stopping things, once they'd started. It's really gruesome and awful. But for the story, it's perfect. That scene was out of control. But by that point, so are the characters."

Woolcock's free way of filming opened Guillory up, letting out sides of herself she'd never shown before. "I felt a lot braver," she says. "Because reading the script, they should probably have cast someone vulnerable and human in a soft, lovely way, like Emily Watson. Someone slightly vulnerable and...sweet."

Is Guillory not vulnerable, then? "I don't know. I didn't become an actor because I like myself," she says. "I became an actor because I wanted to know what it was like to be other people. Because possibly I don't like myself."

Even acting's escape into other roles hasn't allowed Guillory relief. "I hate acting," she says. "Really hate it. I kind of fell into it sideways. I was at a posh all-girls' school, but I didn't have any friends there. I started acting because I got offered a job when I was 16, and they wanted to pay me £8,000, and we'd always lived on Family Support, and I'd been to school with people who could afford to buy jeans and trainers. And I had to steal them. I eventually got expelled for stealing."

She sighs. "I acted because I was so scared of going to university and being with people my own age again, having been with that tiny little sect of girls in Norfolk whose daddies were farmers and politicians, who didn't trust me and didn't know where I was coming from."

Acting was her way out. But soon, she felt trapped by it, too. "The acting was always disappointing. Silly stories about nonsense people. I felt really cheated by acting, because I've never really felt anything from it. I don't wanna be the women on television, who are always nice and do the right thing. I want to be the woman who makes mistakes and gets away with it. The Night Porter is my favourite film. Charlotte Rampling is boiling with rage and going, 'I can do it worse. I'm badder, and dirtier than you will ever be, and you'll never break me.' And I just love that."

Instead, Guillory found herself in a series of bizarre roles, such as the US TV take on Helen of Troy. Guillory's career since is studded with half-hearted attempts to sell out and eccentric detours. "That comes from being 25, and going, 'I've done more films than these people. Why aren't I getting those scripts?' Because my films never get released. So OK, I do Sorted, because it's going to get released, and hate every minute of it. You know, I am ambitious, in the sense of, I will eat as much cardboard as I have to swallow, in order to get to a place where I can make a great script."

Resident Evil, meanwhile, was an attempt to switch her troublesome mind off, to lose it in an action movie. It almost worked. "I'd never done martial arts," she says happily. "I said I could to get the part. It made me go slightly mad, because my brain would be spinning all night. But after my big fight scene, where it was just kick, kick, kick, turn, in a freezing graveyard at 5am, I remember coming home on fire, because my brain hadn't kicked in once. Which was really, really a relief."

Playing Guy Pearce's girlfriend in The Time Machine (2002) was flightier still. "It was a studio film that no other actress would do," she explains, "because it's a tiny role, and she gets killed twice - which really appealed to me. Being in a studio picture is like having a cap and playing for your country. I had fun. My dad had just died, and two weeks later I was playing this, 'Oh, Professor!' role. I thought, if I can make this real, then I'm a good actor."

The frustrations of acting in other movies almost made her quit to concentrate on prod-ucing. Seeing Helen Mirren, onstage in Mourning Becomes Elektra, made her carry on.

"Watching her was such a huge thing," she says. "She has that thing that I'm dying to have, that woman of a certain age, Prime of Miss Jean Brodie, Charlotte Rampling sense of not needing to talk or make people happy. I'd like to like myself enough to act like that. Then maybe I could do something as good as The Night Porter - something some other 16-year-old girl can watch, and feel she doesn't have to change into somebody else in order to be alive; something to make you feel you're not unknown."

'The Principles of Lust' is released today