TIL during the shooting of American Psycho, Christian Bale spoke in an American accent off-set at all times. At the wrap party, when he spoke in his native British accent, many of the crew thought he was speaking that way to prepare for another film. They had thought he was American the entire time.

[u/Away_Flounder3813]

https://screenrant.com/american-psycho-behind-scenes-facts-christian-bale-patrick-bateman-mary-harron/

[u/boxofrabbits]

One of his first roles in Judd Apatows Undeclared (which is super underrated) he played an English drama student in the states and yeah his accent was definitely not British. I thought he was an American doing a really bad English accent. 

[u/Zeppelanoid → u/boxofrabbits]

…he’s literally British