Film critics and showbiz commentators were abuzz last night with reports of Natalie Portman’s “steamy” new role in Black Swan, which premiered at the Venice Film Festival.

The film, directed by Darren Aronofsky, is a gritty exploration of the dark side of the ballet world, inhabited by narcissistic egos and marked by brutal physicality. Portman plays Nina, an ambitious dancer faced with the prospect of a younger, fresher girl taking her role. Nina becomes dangerously obsessed and her ability to distinguish dream from reality unhinged.

The film has received generally positive reviews, though is likely to leave some audiences bewildered. Portman has earned universal praise, however, and is already being talked up as a potential Oscar nominee. Her sex scene with the rival dancer, played by Mila Kunis, has garnered most attention, however.

Portman told The Guardian that she discussed the scene with Aronofsky as far back as 2002. “He described it as ‘you’re going to have a sex scene with yourself’ and I thought that was really interesting because this movie is in so many ways an exploration of ego and that narcissistic attraction to yourself.

“I found the psychological impact of that scene to be really challenging and interesting.”

The film is set for a December release.