Fox411 spoke to actor Bill Nighy and has learned that a not terribly sober Keith Richards of the Rolling Stones has filmed his cameo as Johnny Depp's swashbuckling dad in Pirates of the Caribbean: At Worlds End which is shooting in Palmdale, California.

Nighy wasn't on set when Richards came for his big Hollywood moment, but he more or less confirmed a tale that Fox411 had heard earlier:

Richards, no stranger to substances and liquids, was left to his own devices in his trailer before his big scene. That wasn't a good idea. When the time came to shoot, he was a bit "wobbly." To keep him straight, director Gore Verbinski held Richards by the shins.

"You've got to keep straight," Verbinski told him.

"If you'd wanted straight, then you got the wrong man," Richards replied huskily.

Richards' pirate costume, sources say, closely resembles Depp's, with a different colored bandana. The two had such a good time together that Depp kept a souvenir from Richards' short visit: a set of stairs built for Richards to get in and out of his trailer, which he signed to Depp with the salutation, "A step too far."

Pirates of the Caribbean: At Worlds End hits theatres on May 25, 2007.

Pirates of the Caribbean: At World's End was released May 24th, 2007 and stars Johnny Depp, Geoffrey Rush, Orlando Bloom, Keira Knightley, Jack Davenport, Bill Nighy, Jonathan Pryce, Lee Arenberg. The film is directed by Gore Verbinski.