Natalie Portman is dancing with Oscar buzz for her performance as a New York City ballerina who slowly loses her mind in director Darren Aronofsky's 'Black Swan,' in theaters Friday, and she tells ET that one of the biggest challenges -- other than her racy sex scene with Mila Kunis -- was balancing the physical and emotional demands of the role at the same time.
"To do something that's really physically challenging for yourself and also have to act at the same time was hard because sometimes you have conflicting needs," explains Natalie. "Like sometimes you need to have a real confident, go-getter attitude to nail your turn, and then you need to be insecure in the scene, and those demands can clash."
Natalie's demanding preparation for the film began almost a year before filming began.
"I started doing about a couple hours a day of ballet with my trainer Mary Helen Bowers, and then six months ahead of time we added in three hours of ballet plus, like, swimming a mile, plus toning every day, so that was like five hours a day," says the former 'Star Wars' star. "And then a couple months ahead of time we added in the choreography. Benjamin Millepied, the choreographer, started working on the specific pieces we were going to be performing in the film, and so then it was like eight hours a day. So it was very extreme.
"It was an amazing experience, so it was like every minute was relished, but as soon as it was over, I was like, 'Okay, I'm ready not to train and to eat what I want,'" she continues, specifying that she eventually indulged in "pasta and desserts and the usual -- I would just love to have an ice cream cake."
As for that racy sex scene with Mila, a friend of Natalie's from before they worked together on 'Black Swan,' the young star admits, "It was definitely awkward."
So how did they get through it? "Darren was helpful in just saying, 'You know, if you guys just commit to it, then you're not going to have to do it again. Just do it, get it done. If you're shy and try and be giggly and embarrassed all day, you're going to have to do it over and over and over,'" she recalls. "That was a good way of looking at it."
Watch ET for more with Natalie Portman!