Scottish actor James McAvoy accidentally shot his co-star Josh Helman when they were playing around with Bb guns on the set of X-Men: Days Of Future Past.

The Atonement star, 35, enjoyed socialising with younger cast members in breaks between filming the action movie and they particularly loved racing around the trailer, firing Bb air guns at each other.

MCAvoy once got carried away and accidentally shot the newcomer in the face with a pellet, and Helman's fiancee gave him a scolding for the prank.

He tells U.K. talk show host Graham Norton, "There's a young actor called Josh Helman and he plays the young Stryker and he was coming after me, he had it coming, and as I was running away, I flicked one off behind me, so to speak, I just popped it off and shot him right (on his chin) and I broke his skin and I got told off by his fiancee.

"She came round to my trailer and she was like, 'Hey, how you doing, I'm Josh's fiancee, I heard you shot him in the face... that's not cool', and I went, 'Ah, it was just a bit of fun' and she went, 'No, really man... James, take it down a minute, it's really not cool'... and I was like, 'Okay, I'm just going to go phone my wife and cry a bit'."