Gerard Butler nearly drowned his Playing For Keeps co-star Dennis Quaid when a cast boat trip ended in a nasty accident.

The Scottish actor, who appears alongside Quaid, Jessica Biel, Uma Thurman and Catherine Zeta-Jones in the new drama, took over a houseboat during the shoot.

Butler often took his castmates out for trips on a lake when they weren't filming, but he admits one outing on the boat nearly ended in disaster.

He tells U.S. Tv host Jay Leno, "I stayed on the lake and I had this houseboat which was so derelict it looked like it had been abandoned for 20 years... But it worked! So we would take it out on the lake, all the cast... One day Dennis came out with us... We were in this dock, it had three sides to it, which is where we parked it. Then I was driving it out and suddenly I heard somebody shout.

"I turned around... and Dennis was holding on to the dock and the boat is pushing out and his feet are coming (off) and then he falls and he is hanging from the dock with his feet dangling in the water.

"And I have to jump out of the boat, run round and pull him back onto the dock. And now the boat's stuck as well, so I jump in the water, and I'm feeling really bad for Dennis. And I jump in the water and I (realise the water only came up to my chest) and (there I was) thinking, 'Oh no! I've killed Dennis Quad!'"