Actress Olivia Munn slapped TV host Conan O'brien during an appearance on his late-night show on Saturday (11Jul15) as she demonstrated the painful game she and her castmates play in between takes on X-Men: Apocalypse.
Munn and co-stars Evan Peters, Oscar Isaac, Nicholas Hoult, James McAvoy and Michael Fassbender all appeared on the Conan special in San Diego, California, where the actors had been attending the weekend's Comic-Con convention.
During the TV chat, McAvoy and Hoult revealed the castmates had adopted the "slapping game", which involved alcohol and hitting each other.
Hoult was actually wearing make-up to cover up bruises from a recent encounter with fellow Brit McAvoy.
He said, "James hit me pretty hard yesterday and I was bruised this morning", prompting the Scot to chuckle and say, "Really? Yes! Result."
As O'Brien ended the chat, Munn, who plays Psylocke in the new X-Men film, offered to slap the host and when he let her, the cast cheered, prompting the TV personality to joke, "That was the best and worst thing that ever happened to me."