Sometimes playing a ballet dancer onscreen can require almost as much practice, dedication and pain as actually being a ballet dancer, as Natalie Portman found out when she took on the lead role in Darren Aronofsky’s darkly beautiful “Black Swan.”

To play a perfectionist New York dancer running herself ragged for the lead role in “Swan Lake,” Portman began training a full year before filming began, with five hours of work a day — including three hours of ballet class. “The physical discipline really helped the emotional side of the character, because you get the sense of this monastic lifestyle of only working out, which is a dancer’s life,” says Portman. “You don’t drink, you don’t go out with your friends, you don’t have much food, you are constantly putting your body through extreme pain. You get the understanding of the self-flagellation of a ballet dancer.”

While she by no means considers herself a method actress, Portman acknowledges that the intense training was a massive help in getting into the mindset of her character, Nina, who has trained since childhood — and suffered mentally and emotionally for it — to be the perfect dancer. “[Ballet] is a devotional, ritualistic art, which you can relate to as an actor,” she says. “When you do a film, you submit to your director in the same way. Your director is everything and you devote yourself to create their vision.”

And scene

Despite the rigors of playing a character with such heavy emotional baggage, Portman had no trouble leaving the work in front of the camera. “As soon as I finish a scene, I’m back to being me. As soon as I finish a movie, I want to be myself again,” she says of her working style. “I’m not someone who likes to stay in character. This clearly had a discipline that lent itself to me being more like my character when we were shooting than past experiences, but I go back to my regular life after.”