Actress and style icon Sienna Miller plays Warhol muse Edie Sedgwick in new film Factory Girl. She talks to Eloise Parker about getting under the skin of the self-destructive socialite.

YOU would be forgiven for recognising Sienna Miller more for her red carpet appearances and much-publicised dalliance with Jude Law than for her acting prowess.

With both Sienna and the late Edie Sedgewick having clearly exceeded their 15 minutes of fame, it's tempting to draw comparisons between the two whip-thin, 20-something blondes who've both made more headlines for their dress sense and public appearances than for their art.

But while Edie embarked on a self-destructive route from glamorous 60s girl-about-town to drug addiction and death aged 28 in 1971, Sienna's transformation from tabloid fodder to bankable actress is well under way.

She will next appear in the indie drama Interview, opposite Steve Buscemi, and fantasy adventure Stardust with Robert De Niro and Michelle Pfeiffer.

"It was very difficult to feel what Edie felt," says Sienna. "I've never been sexually abused, I don't have a problem with drugs, and it's really hard to feel that pain. I'm genuinely a happy person and she was really tortured."

"For me, there was so much more to her than celebrity.

"She was a performance artist and she had the magnetism of Marilyn Monroe or Audrey Hepburn, but she destroyed herself."

Two of Edie's major relationships are covered in the film - her close but troubled friendship with Andy Warhol (Guy Pearce) and her brief, intense romance with musician Billy Quinn, played by Hayden Christensen.

The latter raised eyebrows, not only for Hayden's uncannily Bob Dylan-like demeanour - which caught the attention of the real Bob Dylan's lawyers - but also for the pair's sizzling sex scene.

Sienna created a media frenzy when she "channeled Edie one last time" - turning up at the New York premiere after-show party wearing Edie's signature big-knickers-over-tights ensemble.

Explaining the much talked about look, she says: "Edie used to do jazz ballet. She'd put on her tights and her leotard and dance around her apartment and that's how she kept trim.

"She was too lazy to change so she'd put a big coat on and go out, and everyone started copying her.

"It was a totally inadvertent look which caught on."

The 25-year-old says she got plenty more inspiration from the Factory Girl film's wardrobe department.

"I honestly loved every single item of clothing," she enthuses. "It was such an original way of dressing. Some of Edie's photos look like they were taken in the 80s."

Sienna is still trying to get her hands on a particular favourite - a red and black striped dress.

"I'm still battling with producers to find it," she smiles.

"That's something I'm working on, believe me, very hard."