Michael Keaton has revealed the piece of advice Jack Nicholson gave him while filming Batman in 1989.

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Keaton, who is about to reprise his role as the Caped Crusader for The Flash, recently spoke of a private conversation he once had with Nicholson, in which his co-star supposedly encouraged him to ride on the success of a box office hit and follow it up with several “flops”.

“In the old days, I remember I was in London with Jack Nicholson, we were doing Batman, and he was going somewhere, and he said, ‘Come along with me,’ which is an experience in and of itself,” Keaton told The Hollywood Reporter during a Drama Actor Emmy Roundtable, which also featured Oscar Isaac, Tom Hiddleston, Samuel L. Jackson, Brian Cox and Quincy Isaiah.

“So, we’re in the car and he’s talking about the movie. And we all knew it was a huge risk, and if it goes down, [I’d be] going down in flames and that’s going to be a big, hard recovery.

“But I also knew if it worked, it could change my landscape,” he continued. “So Jack says, ‘Keats, if this thing’s a hit, you can go out and do four or five flops and not even worry about it.’ And maybe it wasn’t four or five, but it used to be you got away with three and it didn’t matter.”

However, Keaton stressed how such an attitude would no longer work today. “Not now, man,” he said. “You’ve got one miss, which is fucked up.”

The Dopesick star went to explain to his fellow actors how it’s no longer possible to “cruise” on any given job and not perform to the best of your abilities.

“You get there and the work’s the same, man. Even if you’re going to do a 15-second ad for Vaseline, you say, ‘OK, man, I’m all in,’” Keaton added.

“Because for that minute, I don’t know how to not be all in, not because I’m so fucking groovy, because I probably have a fear of lying down, of going, ‘Well, don’t be a dick. Do the work.’ You know what I mean?

“Every time I think I’m going to cruise on this one, I can’t. You can fight it all you want, but it’s in you somewhere.”

In addition to The Flash, Keaton will also reprise his role as Batman for the upcoming Batgirl film, marking his fourth turn playing the iconic DC hero.