Everyone remembers Jack Nicholson as the perfect villain in the classic 1989 Batman movie directed by Tim Burton. Michael Keaton played Batman and for a lot of kids he is their definitive version of the classic character. Personally Adam West will always be my favorite, but to each their own.
Nicholson played the Joker and he played him very well. The big smile, the goofy dancing, and that iconic laugh. All of it was pretty amazing, but it actually could have been a lot different than we remember.
Sure, Michael Keaton wasn't the only person Burton had in mind for Bruce Wayne, he actually had a couple other actors who were almost cast instead.
Apparently it could have been Alec Baldwin, Tom Hanks or even Bill Murray as the caped crusader, but none of that is as surprising as the news about who was almost the Joker.
The Joker needs a good deal of commitment if you want it to work, the character is genuinely insane and if you aren't 100% in character it will come out looking stupid. Finding a good character actor like that who could stand out when their face is painted white and their suit is bright purple takes a very special person.
Robin Williams was also in consideration at the time but the surprising news is actually from John Lithgow who has told the story of how he almost became the Joker!