Credit: Dave Allocca/


While preparing for her role in the psychological thriller Black Swan, Natalie Portman shed 20 lbs off her petite 5'3" frame. "I had never gotten that much training - to be doing five-to-eight hours a day of [it] was really a challenge," Portman, 29, told on Monday.

Under the guidance of former professional ballerina, Mary Helen Bowers, Portman trained for up to 8 hours a day with only one day off per week. "The goal was to create a very long, lean ballet-type body," Bowers, who developed the Ballet Beautiful classes, told Us at Tuesday night's premiere of Black Swan in NYC.

Bowers supplemented ballet sessions with swimming, cross-training, and endurance exercises. "We combined swimming a mile a day with two hours worth of Ballet Beautiful exercises, toning, and resistance work. And another 3-plus hours of ballet class and point work."

In order to find the time for the intense workouts, Portman had to start the program in the early hours of the day. "We were working at 5 in the morning for two or three hours, and she worked a 12 to 14-hour day on set," Bowers told Us.