Natalie Portman Unruffled by 'Black Swan'

At the 2010 AFI Fest Presented by Audi premiere of the film, Portman told "Extra's" Terri Seymour, "It's a very disciplined environment and the physical training was intense. All that pain and rigor bleed into the character," adding, "I have a newfound respect for ballet dancers."

In this psychological thriller, Portman plays Nina, a young ballerina who finally gets her big shot when she's cast as the Swan Queen in a production of "Swan Lake," however, there's a rival dancer (played by Mila Kunis), who threatens Nina and sends her into a spiral of self-doubt -- and self-destruction.

"I wasn't eating as much as I would have liked," Portman admitted, "But I was still putting fuel in, to keep up the energy I expended."

Director Darren Aronofsky concurred, saying, "I was a little nervous for Natalie. It was a tall order to fill, and she was eating carrot sticks and almonds for a year," but he added that her performance was amazing.

Why a film on the ballet world? Aronofsky replied, "My sister was a dancer, very talented, but I knew very little about it. It's a unique world and the idea of doing a horror film in that world was exciting."