Apparently, when the 1989 Batman movie was in casting, Willem Defoe was one of the options to play the Caped Crusader. I'm not sure exactly how this would have worked out, but Defoe's prior work has proved that he has the ability to go dark enough to be able to pull off the persona of The Dark Knight, but I'm not quite sure how his Bruce Wayne would have felt.
This bit of news that broke from MTV Splash Page early on Tuesday definitely appears to be odd when you first hear about it, but when you sit down to think, he might have done a fantastic job.
Either way, Willem Defoe as Batman is a Hell of a lot better than Nic Cage as Superman, so thank God for that.
Source: MTV Splash Page