Sound Off: Worst Casting Ever

David Cronenberg's A Dangerous Method - in all its Keira Knightley overboard glory - I started reminiscing a bit on those frustrating moments in cinema acting. You know the ones. The film is fine, teasing with the notion of greatness, when all of the sudden 'that' person comes onto the screen. In any other role, in any other film they'd be a legend, mesmerizing star whisking you off your feet with each and every movement. Here, however, they're chewing up more scenery than a goat on speed. And it's such a shame because with each effort they make, the film just falls farther and farther from grace. Maybe in multiple viewings you're able to drop that agitation. Maybe you've come to accept it and overlook that performance for the greater good of the overall picture. But the fact remains that the film forever suffers for that one poor casting decision.

So, I ask you - What is the worst performance you've seen in a movie you love, or would have loved otherwise?