I rewatched the film named "Ex Machina" the other day. The lead actor, Domhnall Gleeson, starring as Caleb in the movie. I originally thought he is American the first time I saw this movie one year ago because he speaks an American accent and says he grew up in Portland, Oregon in the movie. Then, about half a year ago, I saw another movie, "About Time", starring him too. However, in this movie, he speaks a British accent. So, I guessed he might be British. Recently, I rewatched Ex Machina and carefully listened to his dialogue in the movie. I got so curious that I googled this actor and found that he is actually Irish. How come actors and actresses are so talented that they can freely shift from one accent to another?