Michael Keaton: Reprising Batman for 'The Flash' was 'like riding a bike'

It took nearly 30 years after Batman Returns for Michael Keaton to return as Batman/Bruce Wayne, but he doesn't feel like any time has passed at all.

"Like riding a bike," the 69-year-old actor said of reprising the role when asked what it felt like to be back in the Batman suit on Wednesday night's (Aug. 18) The Tonight Show Starring Jimmy Fallon. "Hey, man, here's the thing I learned—I was so stupid to think, you know, when I was first doing it I got in really good shape, which you have to get into shape because you just have to carry the thing around. I don't know why I didn't think of this the first time. It's easier to be really skinny and not work out because you have more room to work around [in the suit]."

"The first time I was doing it, the first one, I'm getting ready," he continued. "I'm working on the [punching] bag, and I'm doing all this stuff. And Jack Nicholson walks by, who was playing the Joker, and he looks at me and goes, 'What are you doing?' I go, 'You know, working out.' And he goes, 'What for?' I stopped, sweating, and I went, 'I don't know.' And he just walked away. I thought, he's right. Totally right. 'Cause you got a suit. What do I need to do? The suit makes me look good."

Keaton debuted as Batman in the1989 Batman film directed by Tim Burton, and he continued in the character for the Batman Returns sequel in 1992 before Val Kilmer took over for 1995's Batman Forever. Now, Keaton is reprising the iconic superhero role for The Flash directed by Andy Muschietti. The movie will also feature Ben Affleck as Batman.

"The Flash takes inspiration from the Flashpoint arc from DC Comics, which sees the Scarlet Speedster running so fast using the speed force that he actually teleports to different parallel realities," writer Nick Romano explained for Entertainment Weekly in April. "It's a concept teased in Snyder's Batman v Superman and the recently released Snyder Cut of Justice League on HBO Max. That explains the multiple Batmen."

Keaton spoke more in depth about his anticipated return in the new cover story for The Hollywood Reporter.

"Frankly, in the back of my head, I always thought, ‘I bet I could go back and nail that motherf—ker,'" the Birdman Oscar nominee told the publication. "And so I thought, 'Well, now that they're asking me, let me see if I can pull that off.'"

Keaton added: "What’s really interesting is how much more I got [Batman] when I went back and did him. I get this on a whole other level now. I totally respect it. I respect what people are trying to make. I never looked at it like, 'Oh, this is just a silly thing.' It was not a silly thing when I did Batman. But it has become a giant thing, culturally. It's iconic. So I have even more respect for it because what do I know? This is a big deal in the world to people. You’ve got to honor that and be respectful of that. Even I go, 'Jesus, this is huge.'"

Watch Keaton's full Tonight Show appearance below.