After pirouetting for hours on the set of "Black Swan," Natalie Portman would sometimes remove her pointe shoes, towel the sweat off of her brow and be met by a disapproving critique from director Darren Aronofsky.
"He'd say, 'Oh, Mila is doing really well on her stuff. She's so much better than you,'" the 29-year-old actress said, referring to her costar, Mila Kunis. "Darren would tell us things about each other to try to make us jealous. I think he was trying to create a rivalry in real life between us."
That Aronofsky may have tried to stoke competition between his lead actresses is understandable — envy is at the core of "Black Swan," a mystical ballet thriller in theaters Friday about an uptight dancer named Nina (Portman) who becomes obsessed by the threat posed by blithe new company member Lily (Kunis). The young women are vying for the lead role in "Swan Lake," and while Nina can perfectly encapsulate the virtue of the white swan, she struggles to convey the sinister, sexual nature intrinsic to the black swan that seems to come naturally to Lily.
Although Portman and Kunis were longtime friends — they often hung out together in Los Angeles, watching "Top Chef" or sifting through vintage wares at the Rose Bowl Flea Market — the director kept the two apart for nearly the entire 42-day filming process.
"We were really great friends before production. We are really great friends now. And during production, we were working together," Kunis, 27, explained.
Aronofsky denied fueling a rivalry but said he distanced the actresses so that they couldn't discuss their respective acting approaches.
"I knew it might be really hard to keep them apart because they're friends, but I just didn't want them to know each other's motives," he said. "I didn't want them to compare notes. I wanted them to come from different places."
Aronofsky, the filmmaker behind "Requiem for a Dream" and the 2008 Mickey Rourke comeback picture " The Wrestler," had his own foes to overcome to get "Black Swan" made. He decided nearly a decade ago that he wanted to do a film about the ballet world, but several ideas and scripts bogged down in development and the project lost and regained financing numerous times.
The director first met with Portman when she was 20. She had taken ballet classes as a girl and had always imagined she'd be a dancer if she weren't an actress, so she was struck by Aronofky's idea. As "Black Swan" remained in limbo, she acted in other movies, such as Zach Braff's "Garden State" and two "Star Wars" films.
While Portman was long slated for the movie, Kunis (best known for her role on the long-running sitcom "That '70s Show") was brought in only months before production began. Portman, who knew that Kunis had dance experience, recommended her friend to Aronofsky. He had seen Kunis in "Forgetting Sarah Marshall," and the two met via iChat. A few online video conversations later, he had hired her.
But from that point forward, the actresses had little interaction. Their lack of conversation is particularly interesting, considering they largely play the same character for much of the film. As Nina becomes paranoid about Lily stealing her role, she begins to have delusions — sometimes she believes she's looking at Lily, only to realize she's visualizing a darker and more liberated version of herself. The fluidity of that relationship culminates in a heated sex scene between the young women, which is teased in the movie's trailer and has for months been the subject of media fascination.
It was one of the few scenes the actresses shot together, and Portman — whose character also masturbates in the film — described it as "super awkward."
"I remember the first time we did it, we were both sort of embarrassed and not going for it," she said, sipping vegetable broth at the Polo Lounge in Beverly Hills. "And Darren was like, 'Listen. If you go for it, you're not going to have to do it again. If you get all embarrassed and hesitate, you're gonna have to do it 400 times.'"
Kunis said Aronofsky promised the actresses the film wouldn't leave his hands until it was released so that the scene wouldn't go viral on the Internet. Crew members had their cellphones confiscated so that they couldn't take any photos of the steamy segment.
Meanwhile, Kunis, who with the rest of the "Black Swan" cast has spent the last couple of weeks promoting the film, said she was irritated that she had received so many questions about the racy moment.
"How people walk away from a movie like this and the first question out of their mouth is 'Is it uncomfortable making out with your friend Natalie?' — it's unfortunate," she said in a separate interview a few days later. Reporters have also been asking both Kunis and Portman about their trysts in their next films, which are strikingly similar, centering on women in casual relationships. (Kunis is starring in "Friends With Benefits," while Portman is in "No Strings Attached.")
Both women would prefer the interest be focused elsewhere — like on the rigorous physical preparation they put into transforming into near-professional ballerinas. Even as the film struggled to get off the ground because of financial issues, Portman began training five to eight hours a day with a ballet instructor. She spent time in barre class, swam a mile each day, did toning and muscle strengthening exercises and sharply reduced her calorie intake.
"Darren claims he never said this, but he definitely was like, 'How thin do you think you can get without being sick?'" Portman said. She apparently took that order so seriously that the director later began to fret over her shrinking frame.
"At a certain point in the middle of the ballet stuff, I thought she was getting way too skinny and I started to make her eat. It started to get scary, and she was starting to look too thin," Aronofsky admitted. "But when you work in the world of ballet, these women are so tiny. I just didn't want her to get hurt, so we surrounded her with the right health people."
Both she and Kunis, already short and slight, lost 20 pounds before production even began.
"I looked like Gollum," Kunis joked, referring to the emaciated, bug-eyed creature from "Lord of the Rings." She said she got down to 98 pounds. "I did not veer off the diet. I got one day off on my birthday, and I did have a root beer float. My ballet instructor was like, 'Here's your present!'"
The women each suffered injuries during production — Portman dislocated her rib and Kunis dislocated her shoulder and tore two ligaments — but continued dancing despite them.
"She was really living the life of a ballerina in many ways because of the way she was training and that sacrifice," said Portman's dance teacher, Mary Helen Bowers. "We would meet many days at 5 in the morning, she would go and work a 12-hour day on set and then meet me at the ballet studio or gym afterwards. She wasn't going out with the cast and having beers. It was a different kind of work experience. And I think that's really the life of the dancer. It's so hard on you physically that you just can't really live a normal life."
Portman had imagined that there would be strong parallels between the worlds of acting and dance but found herself startled by the particularly cutthroat environment of ballet. Especially because in the last few years, she said, she's begun to abandon her own jealous instincts — particularly when she's up against another young actress for a part.
"It's age, dude," she said of her growing self-acceptance. "I've definitely had competitive moments, but I think the difference is now that I really feel like I know who I am. I think a lot of girls have this thing where if you're in a bar, you sort of size up the other girls in the place to be like, 'Who is my competition?' And that's not even in my mind anymore. If someone is, like, 'I don't know whether I should hire Natalie or blahblah,' I'm like, 'You don't know what you want.' I am who I am, and I like who I am."
Her confidence impressed Barbara Hershey, who plays Nina's overbearing mother in the film.
"At 29, I was not together like Natalie is together," Hershey said. "The fact that she was kind always and never complained and was always even with everybody, that was impressive. It was a lot to shoulder, this film. And while all actors would dream to have parts like that, the actuality of doing it is another thing."
Portman's performance has already prompted many pundits to declare her a frontrunner in this year's best actress Oscar race. She was nominated for an Academy Award once before, for her supporting role as a stripper in Mike Nichols' 2004 "Closer."
"I was studying abroad in Israel during that, so I was kind of out of the loop," she said. "But I've been doing this for like, almost 20 years now. And I don't get awards. And I feel really lucky, because it's not part of my calculus."
The actress, whose first notable role came at age 13 in Luc Besson's "The Professional," grew up largely on film sets. It wasn't until she attended Harvard University that she says she was able to find her own voice, abandoning the "yes, ma'am" attitude she'd adopted during adolescence.
"When you're a child, and a director is telling you what to do, you're just like, 'OK.' It's like it's your parents," she recalled. "There are certain people that have personalities, even as kids, where they're like, 'No! I won't do that!' But that's just not me at all."
Having to tap into that side of herself while playing the deferential Nina, she said, was more challenging than nearly all of the physical work.
"I was a good kid, and I probably stayed in that phase longer than most kids. I think even into my early adulthood, I was like, 'Yes, thank you, sorry,'" she said. "Having that apologetic, pleasing side to me — I've worked really hard to get out of that. Now, if I want something different, I'll say it. Darren learned one day that after trying everything he wanted to do, if on the last take he said, 'Do this one for yourself,' that's the one that would be my best."