Mila Kunis, star of Friends with Benefits, has Heterochromia. The actress has one brown eye, and one greenish hazel eye.

Heterochromia simply refers to a difference in color in the iris. It's the result of a lack of melanin in one eye, hypoplasia. This can be caused by genetics, or damage to the eye. And although it's uncommon in humans, it's relatively common in dogs.

In other Kunis news, the actress has accepted an offer to attend a Marine Corps Ball with Sgt. Scott Moore in November. The actress accepted the invitation as she was doing press for her upcoming comedy, Friends with Benefits, co-starring Justin Timberlake.

Moore asked Kunis out because of a bet, and in an attempt to get the 27-year-old's attention, Moore set up a YouTube page and filmed a short video with a personal invitation to Kunis. The video has been viewed over 200,000 times with comments ranging from, Hope she says yes! Good Luck! to Good idea but came off a little creepy. Creepy or not, the Black Swan actress has accepted the invitation making Moore one happy man.

When Justin Timberlake heard about the video, he said to Kunis Have you seen this? Have you heard about this? You need to do it for your country.

Mila Kunis got her start acting way back in 1995 on The John Larroquette Show where she played Lucy for one episode. It wasn't till over 10 years later that the actress rose to stardom with That '70s Show. The raven-haired beauty graced the TV as the demanding Jackie Burkhart, playing opposite of Ashton Kutcher. In 2006, Kunis became the voice for Meg Griffin on the Family Guy, and then in 2008 Kunis appeared as supporting actress in Forgetting Sarah Marshall.

Last year Kunis appeared in Black Swan, a film that garnered Natalie Portman an Academy Award for Best Actress. Currently, Kunis is filming Ted (2012) and has Oz: The Great and Powerful in pre-production.

Friends with Benefits opens on July 22.