Mila Kunis Reveals She Did 'Very Little Eating' During 'Black Swan' Prep

In an interview with Vogue alongside her Black Swan co-star Natalie Portman and the film's director Darren Aronofsky, the actress opened up about her grueling training to prep for her role as a ballet dancer in the 2010 psychological horror film, while also detailing the intense filming process, including how she suffered an injury during production.

"My prep was a lot of dancing and very little eating -- which I know you're not supposed to say, but it’s the truth. I drank a lot of broth and danced for 12 hours a day," recalled Kunis, now 42, who was 27 while filming.

Kunis said she and Portman were initially only set to have three months to prepare to portray professional ballet dancers, but due to budgeting, they ultimately had six, which worked in their favor.

"We were only supposed to have three months of prep before filming started, but we lost some financing, so that got extended to six months while Darren tried to find money," she explained. "It sucked for Darren, but Nat and I were so happy because we had three extra months to dance."

Portman chimed in, recalling how she gained "insight" into the world of ballet.

"One of the most surprising side effects of doing the physical training was that I ended up spending a year talking extensively to my trainer, who was a former New York City Ballet dancer and told me hours of stories that gave so much color and insight into that world. It was like doing investigative journalism, but I was just gossiping with her while doing pliés," she recalled.

Meanwhile, Kunis went on to recall how she injured herself early on during the shoot.

"We would shoot those dancing scenes for hours, and I had bruises all over my ribs just from being lifted over and over again," she shared. "I also dislocated my shoulder pretty early in the production and thought I was completely screwed, but Darren sent me to an acupuncturist and I somehow came out totally fine."

In Black Swan, Kunis starred as Lily, a newcomer and rival to Portman's Nina, with the two competing for the role of the lead ballerina in Swan Lake.

During the Vogue interview, Aronofsky revealed that he tried to create a rivalry off-screen to help with Kunis and Portman's performances on-screen -- but his efforts backfired as the two actresses figured it out.

"My take is that I was trying to be a sneaky director and make them argue. Mila and Natalie both realized very quickly what I was doing and made fun of me, so it quickly became a joke that we all understood," Aronofsky said. "They’re both very clever and were instantly privy to whatever trick I was playing."

"Do you guys remember it differently?" he asked Kunis and Portman, who remain good friends.

"I remember being separated from Mila and that we weren’t in the same space a lot when we weren’t shooting. Darren made some comment early on, like, 'Ya know, Nat, Mila’s dancing so well,'" Portman recalled. "And I was like, 'Of course she is! She's so f--king talented and I love her so much and I’m happy she’s doing a great job!'"

Kunis shared, "Darren would tell me, 'Nat is working really, really hard. She's not even taking Saturdays and Sundays off.' Then I would text Nat and she'd be like, '…No, I’m not?' I think that's how we figured out what Darren was up to, but it was all in good fun."

Black Swan -- which premiered at the Venice Film Festival in September 2010, and was released that December -- was praised by critics and earned five Academy Awards nominations, including Best Picture, Best Director, Best Actress, Best Cinematography, and Best Film Editing. Portman ultimately won the Oscar for Best Actress.

In honor of the film's 15th anniversary, Black Swan is returning to theaters next week and will be released in IMAX for the first time, according to Deadline.