As the star of Tim Burton's "Batman" movies, Keaton was the first actor to decide that Bruce Wayne and the Dark Knight could not share the same voice. The Golden Globe-winning actor sat down with Josh Horowitz on the Happy Sad Confused podcast, and explained why he arrived at that choice.
"I'm kind of a logic freak," he said. "I don't know how to do anything unless I have a logic to it. It can be the silliest, stupidest, broadest thing, but I have to work from somewhere."
Keaton encountered a serious logic problem during his first scene shooting as the Caped Crusader, in which he confronts a criminal in a dark alley.
"There's no way this guy doesn't just look at me and say, 'That's Bruce Wayne, everybody! I figured it out!'" he said with a laugh. "'It's obviously you! You're four feet away from me!'"
Burton and Keaton explored a few different ways to preserve Batman's identity in the scene, from the way he was positioned, to the use of contact lenses. Ultimately, the only thing that made sense to Keaton is if Batman used a different voice than the famous Gotham City playboy.
"I had to do something," he said. "I had to drop down a register. Then I learned, later, that it became a thing [for future 'Batman' movies]."
Looking back on it now, and even at the time, Keaton was an unlikely choice to take on the DC Comics superhero — a fact that's not lost on Keaton at all. He said he had to find some extra layers in Batman and Bruce Wayne beyond all the grim-and-gritty, lending levity to scenes like his dinner date with Vicki Vale, in which she and Bruce sit across from each other at a long dining table in a room he's never entered.
"It's funny, but it's also kind of pathetic, and not serious pathetic," Keaton said of the scene. "Then, in the next couple of minutes, this guy gets to go out and kick somebody's ass. That guy, and that guy, was very interesting to me."