Sienna Miller's sex scene with Hayden Christensen in her new movie is so steamy it has prompted speculation it might be more than acting.
Those who have seen Factory Girl say the sizzling clinch is even saucier - and more revealing - than the famous are-they-or-aren't-they love scene between Julie Christie and Donald Sutherland in 1973's Don't Look Now.
But Miller's publicist insisted the sex was not real. "She's just a really good actress," she told the New York Daily News.
The 25-year-old plays Andy Warhol's beautiful but doomed protege Edie Sedgwick in the movie.
Unconfirmed reports have claimed Miller and Star Wars actor Christensen, who plays her folk rocker lover, were romantically involved off-screen as well.
Director George Hickenlooper told the newspaper: "Sienna and Hayden grew close during the filming. It was an emotional experience for all of us."
But quizzed about whether the lovemaking was real, he said: "I can't comment. You'll have to ask Sienna about it."
Last year, Christie finally put an end to the old rumours she and Sutherland were not just acting in their ultra-realistic sex scene.
"Of course it was pretend, but it was hard for both Donald and I," she told Psychologies magazine.
