Ashton Kutcher has pledged to get serious about his movie fighting techniques after accidentally knocking out a stuntman on the set of his latest film.
The actor reveals he signed up for Fillipino knife fighting lessons and did some training to get into shape for new action comedy Killers - but was far from ready for combat on the set.
He tells WENN, "I bought those exercise DVD tapes off the TV and that's how I got in shape and I did some fight training and then I realised I should learn how to movie fight because, in the first fight scene, I knocked out a stunt guy.
"We were on a yacht in the wind and the boat was shaking and he threw a punch and I blocked it and I punched him and knocked him out. I felt really bad about that.
"And then I kicked (co-star) Rob Riggle in the face. I hurt a lot of people. I just should've let the stunt guy do everything to be perfectly honest and stick to just making jokes!"