Mila Kunis is undoubtedly one of the most beautiful women in Hollywood. And even though they say there’s more to beauty than what meets the eye, part of Kunis’ allure actually lies specifically in her eyes.

Kunis became a household name after landing a role on That ’70s Show at a scandalously young age. And while there were many secrets the cast tried to hide, Ashton Kutcher’s lady love had a secret of her own about her eyesight. It’s not widely known, but the gorgeous brunette has had two different colored eyes — and the reason why is actually a little scarier than you might expect.

Mila Kunis was partially blind

The actress is one of a handful of celebrities with a condition called heterochromia which is “characterized by color differences of the iris,” according to the National Center for Advancing Translational Sciences. Upon first glance, you might not notice anything different about the Bad Moms star’s smoldering gaze, but if you look a little closer you’ll see that her left eye is green and her right eye is almost brown. But this wasn’t a condition she was born with.