Courtesy of Cosmopolitan

"Black Swan" siren Mila Kunis was blind in one of her eyes when she was filming the ballet thriller and only recently had surgery to correct it, she reveals in the February issue of Cosmopolitan magazine.

"I was blind in one eye for many years, and nobody knew," Kunis told the mag. "I'm not blind anymore. I had surgery a couple of months ago. They cut it open and dropped a new lens in there."

So much gross-out information! Especially in a magazine where we expect to hear about things like sexual positions, boob jobs and who's a better kisser: Ashton Kutcher or Natalie Portman. Thankfully, Cosmo didn't disappoint. On the topic of Kunis' favorite onscreen smoocher, the actress was terribly diplomatic.

"Justin's (Timberlake) upper lip...Natalie's (Portman) bottom lip...Ashton's (Kutcher) stubble...James' (Franco) chin...and Jason's (Segel) teeth," Kunis said.

We would have gone with Franco's stubble and Portman's teeth, but that's just personal preference.

Kunis chatted candidly about co-stars and medical problems but remained tight-lipped about her relationship with actor Macaulay Culkin, which recently ended after the couple spent eight years together.

"The reason I'm able to have a relationship is because I don't talk about it... Never have, never will," Kunis said.

To read all of the interview, pick up next month's issue of Cosmo.

Meanwhile, check out Mila's style evolution.