What are some roles that surprised you after finding out the actor was using an accent?

Christian Bale as Patrick Bateman is the main one that comes to mind. Hard to picture him as British after seeing American Psycho. I wonder if it’s easier to embody and embrace a role when you’re forced to have an accent. I can’t think of many American actors that have had to don a British accent other than recently with Sam Rockwell in See How They Run. Either way, it seems like a difficult task that requires a lot of talent and focus.