Sunset Boulevard via Getty Images Michael Keaton in the 1989 film "Batman." Keaton recently explained why he quit the franchise after two films.

Michael Keaton held the title role in Tim Burton’s “Batman,” the highest-grossing film of 1989. He also starred in the sequel, “Batman Returns,” which was the third biggest movie of 1992.

And then he walked away when director Joel Schumacher took over the franchise for the third installment, “Batman Forever.”

Now, Keaton has explained why he left despite all the success, and the answer is pretty simple: He didn’t like the script for the third film.

“It sucked,” Keaton told The Hollywood Reporter’s “Awards Chatter” podcast. “The script never was great. I didn’t understand why (Schumacher) wanted to do what he wanted to do.”

Keaton said he attended “many meetings” over the film, and was “polite up to a point about things.”

But he didn’t like the new direction Schumacher had in mind.

“I knew it was in trouble when he said ‘Why does everything have to be so dark?’” he said.

When it came down to it, Keaton said he just couldn’t do it.

“Not like, I’m above it, or an artist, but maybe I’m enough of an artist to go, ‘I just don’t think I can do this without blowing my brains out,’” he said.

Given that the Schumacher “Batman” films also introduced the infamous nippled Batsuit, Keaton’s instincts seem to have served him well.

Check out the full podcast, an hourlong discussion of Keaton’s career. It includes highlights such as “Batman” and Beetlejuice” and his latest role: McDonald’s visionary Ray Kroc in “The Founder,” which is generating Oscar buzz.