Olivia Munn earned a black belt along with her brothers and sisters. Below is what she said martial arts means to her:

“All of us started karate at around age five and studied it until we were about 16 — and we weren’t allowed to stop practicing until we had achieved black belts. The things that stayed with me the most from that training were the discipline not to give up when something feels too hard and the confidence that comes from knowing that if I keep working hard, I’ll achieve my goal, even if it feels impossible.”

I was unable to determine if her black belt is in Karate or Taekwondo as articles all over the web have it listed as both. If you search for her you can find a couple of videos, one of her showing off sword skills and one of her showing off some round kicks and a hook kick.