Jack O'Connell's heavy regional accent left his Japanese co-star Miyavi struggling to understand him on the set of Angelina Jolie's film Unbroken.

British actor O'Connell spoke with an American accent to play World War Ii hero Louis Zamperini, but singer Miyavi was left baffled when his co-star slipped back into his native tongue.

He says, "I can understand what everyone says apart from him. Jack plays the film's American hero, so spoke with a U.S. east coast accent that meant everyone understood what he was saying while we were shooting. But once the cameras stopped rolling Jack would revert to his native accent, so I'd need my dialect expert on hand all the time to let me know what was being said."