'Prison Break' star punched by Sutherland

Robert Knepper has revealed that he was once punched by Kiefer Sutherland.

Speaking to DS, Knepper - who recently joined the cast of Heroes - admitted that when he announced to Sutherland that he may quit acting, the 24 star reacted by punching him.

He said: "10 or 15 years ago, Kiefer used to go to the same gym as me. I remember telling him that I wanted to quit. It was before Prison Break and I couldn't find any work and I wanted to quit.

"He f**king punched me! He punched me so hard. He told me, 'Don't you ever give up!' and I thank Kiefer every day for that advice."

Earlier this year, Sutherland was charged with assault after allegedly headbutting a fashion designer.