The film's director Aronofsky stated in a July 2010 interview that: "Most of these women who are here started dancing when they were 4, 5 or 6 years old. Their bodies are shaped differently because they started so young. She was able to pull it off. Except for the wide shots when she has to be en pointe for a real long time, it's Natalie on screen. I haven't used her double a lot.
In a November 29, 2010 interview, Portman's other dance double, Kimberly Prosa, stated: "Natalie took class, she studied for several months, from the waist up is her. Sarah Lane a soloist at ABT, did the heavy tricks, she did the fouéttes, but they only had her for a limited time, a couple of weeks, so I did the rest of whatever dance shots they needed."
Earlier this week Sarah Lane said that Portman only performance 5% of the dancing in the movie - something which was denied by director Darren Aronofsky via a statement from the film company.
Speaking to E! Online Sarah Lane said: "It was all my fault really because I didn't have a manager.
"I thought they would kind of take care of me because they were really encouraging and really sweet and always saying how amazing I was.
"They were kind of rooting me on when I would have to do shots that were really hard and almost impossible even for a professional ballet dancer."
In another interview with The Wall Street Journal, Sarah Lane states that she was asked by a producer to stop giving interviews "until after the Oscars" and states that she "had read a lot of articles that Natalie had done where she said she did 90 percent of the dancing. And never mentioned my name once. Nobody ever mentioned my name hardly ever. I’m not stupid, I got the idea that they really want to make it look like she had accomplished something incredible. And I do want people to know that she did work really hard. And she lost a lot of weight so that if you looked at her you would say she could pass from the arms up as a dancer. She’s an amazing actor. I can’t act like that. But to say that she did all of the dancing is absolutely ridiculous to anyone that knows anything about ballet."