Johnny Knoxville was left stunned by Dukes Of Hazzard co-star Willie Nelson's marijuana intake on the set - because the grizzled country legend could still function perfectly after smoking up a storm. The Jackass star is famous for undertaking crazy stunts on film, but he'll never try to out-smoke Willie Nelson. He tells Blender magazine, "I don't smoke weed much, and his s**t is a commitment. I honestly don't see how he functions - people pass out smoking that. "He had a crew with him shooting a documentary, and one of the camera guys keeled over while filming."