Munn, 35, who will star opposite James McAvoy, Michael Fassbender and Jennifer Lawrence in the superhero film as the telekinetic mutant, said she is in love with her fearless character.
"She's a little scary. She has no problem battling and killing. I love how strong she is."
Munn also revealed she is a certified black belt in karate and practised sword-fighting to get into her character for the film.
"I'm the fourth of five children. All of us started karate at around age 5 and studied it until we were about 16, and we weren't allowed to stop practising until we had achieved black belts."