She trained in ballet for one year, lost 20 lbs., and bruised a rib. Natalie Portman definitely suffered for her role in Black Swan as a mousy ballerina who descends into madness. "There were some nights that I thought I literally was going to die," she told Entertainment Weekly. "It was the first time I understood how you could get so wrapped up in a role that it could sort of take you down." Of course, the fallout from her efforts was anything but a downer: Now pregnant and engaged to her onscreen dance partner Benjamin Millepied, Portman is a front-runner for the best actress Oscar.