Colbert got things started when Willis claimed he still did all his own stunts in his action movies. Colbert then pretended to taunt Willis, "With all due respect, I find that hard to believe that a man who spends most of his time lying down on the job these days actually does his own stunts."
Willis pretended to take offense. There followed a royal punch-up—performed with intercut shots of stunt doubles.
See the clip below: