Apocrypha Now! Urban Legends of the Silver Screen
Let me add something that I suspect of being an urband legend. In The Greatest Story Ever Told, there is a famous cameo for John Wayne. Here's a typical version of the story, from an interview with the late Brandon Lee:
Lee: Nope, no John Wayne. Did you ever hear the story about John Wayne when he was in Greatest Story Ever Told?Well, I suspect it's just a great urban legend. I wonder if there is any way of finding out whether it is for certain though. Some internet sites hint that they think that it is (e.g. here). George Stevens and John Wayne have both been dead for a generation, so no one can now ask them. I wonder if anyone else has ever made an informed comment?
Lee: Well, there he is at the bottom of the cross, Christ is dying, and I believe his line was, "Truly he was the son of God." So he said the line and the director came over to him and said, "You think could you do that with a little more awe?"
He said, "Sure," and so they roll the cameras for a second take and he said, (Brandon assumes a Texas twang) "Aweeee, truly he is the son of God." [laughter] It's suppose to be a true story, I don't know. [Source: Brandon Lee's Last Interview]