Matthew McConaughey has revealed he incurred the wrath of Christian Bale when he headbutted him by accident on the Reign Of Fire set.
The Killer Joe star and The Dark Knight Rises actor appeared opposite each other in the 2002 action fantasy film, and Matthew told Total Film magazine how he hurt the method actor for real during a fight scene.
Matthew said: "That scene where we're fighting and I headbutt him... it was a complete accident. But in the take, I just put it right on his forehead.
"He immediately swelled up like a frickin' tennis ball, but he kept going. I knew I'd screwed up. I looked in his eyes and I saw him go 'Grrrr!' and then we kept going.
"Later he had his moment to be p***ed off at me, which he absolutely deserved. There was no drama about the situation whatsoever, though he wasn't really happy about it."
The 42-year-old hunk stars in new thriller Killer Joe and Stephen Soderbergh's Magic Mike, about male strippers co-starring Channing Tatum and Alex Pettyfer.
Matthew admitted playing a stripper made him determined to get in shape.
He said: "Let me tell you... Six guys, playing strippers? It's the best way to get in really, really, really great shape. I mean, you just sit there going 'I'm gonna be on screen, 40 ft tall? For the rest of time? I'm not having pizza tonight..."