Adrien BrodyWe now know that ersatz 'Prince of Persia' Jake Gyllenhaal can play a lot of film roles -- but convincing action hero ain't one of 'em. And Adrien Brody might have been the youngest man ever to win a Best Actor Oscar (for 'The Pianist' in 2002) -- but that didn't save 'Splice', and we must admit we've raised an eyebrow or two over his playing the lead mercenary in 'Predators.'

So why do casting agents and directors put stars in roles that go against the grain? We don't know. We're just glad they do. Reverse-typecasting has provided us with some of moviedom's most memorable moments -- intentional and not.

Here's our list of the best examples of reverse-typecasting in Hollywood history.

'STAR WARS' -- An Academy and Tony Award winner and renowned star of stage and screen, Guiness shocked his peers when he took the role of Obi-Wan Kenobi in some weird little sci-fi film by an unknown director. But Guinness was shrewd enough to negotiate a piece of the action -- two-percent of the take from Star Wars, which made him filthy rich. He hated the character, and in fact, persuaded George Lucas to kill him off because he "just couldn't go on speaking those bloody awful, banal lines. I'd had enough of the mumbo jumbo." Sir Alec later said he "shriveled up" every time anyone mentioned Star Wars.

CHARLIZE THERON IN 'MONSTER' -- Yuck! Yuck yuck yuck yuck yuck! But she was amazingly good as the last female serial killer executed in the United States.