The small-budget independent picture could become an important boost to Sienna's acting career reports Daily Mail UK. Those who have seen early rough-cut versions say the performances of Sienna and leading man Guy Pearce, as Warhol, are brilliant. So much so that studio chief Harvey Weinstein plans a year end Oscar campaign for them.

"The more I delved into her, the more I realized she'd had this traumatic life," Sienna, left as Sedgwick, told Daily Mail, explaining how her childhood was an emotional nightmare.

She was popping Valium at eight, had electric shock treatment at 14, and was sexually abused by her father. "You can see why she went so wild," Sienna noted, alluding to Sedgwick's society antics in Sixties New York.

The actresss, 24, was fascinated by Sedgwick, spending the best part of a year researching her life, and admits she became "totally obsessed" with the model-turned-muse.

"I found it really hard to take my black tights off," she joked, referring to Sedgwick's trademark nylons But then, more seriously, she added: "Actually, I didn't want to let her go."

Finally, though, Sienna's mother told her to pull herself together. "She said: 'You've got to stop this now.' I took myself off to Mexico co on my own for a week and just chilled out, but it was several more weeks before Edie escaped my system. I think there's still a bit of her in me."