Kenneth Williams(1926-1988)

Kept falling asleep while filming 40 grados de amor (1959), due to the combination of warm studio lights and acting on a bed. When director Gerald Thomas woke him up, Kenny would swear blind that he wasn't asleep. So the next time it happened, Thomas put a sign around his neck, and took a photograph. When Kenny tried to wriggle his way out of it again with protestations of not being asleep, Gerald showed him the photograph - apparently Kenny's language became very colorful.

"Oh, stop messing about" (catch phrase)