Acting legends Marlon Brando and Robert Duvall lightened the mood on the set of The Godfather by flashing their backsides at other cast and crew members.

James Caan, who played Brando's onscreen son Santino 'Sonny' Corleone in the 1972 movie, reveals the on-set pranks in a new picture book, called the Godfather Family Album.

And he insists Brando was the ultimate joker: "They're standing at the wedding ceremony when they posed for that picture, and there are 500 extras, old ladies, old men, kids, everybody. Bobby Duvall sees the ultimate moon. He and Brando had a race to drop their pants and Bobby's got hitched, and Brando beat him, bent over and spread his cheeks and mooned everybody."

"We had this belt made; Moon Champion, hand-tooled leather. Brando got it."

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(This news article provided by World Entertainment News Network)