Michael Keaton’s Real Name Is Michael Douglas. Now, After Decades in Showbiz, He’s Going to Start Using It.

Keaton tells PEOPLE he “can’t remember” if he picked his stage name out of a phone book decades ago

He couldn’t use his birth name, Michael Douglas, since the Screen Actors Guild prohibits members from using another member’s professional name.

The union already had a Michael Douglas (the future Wall Street Oscar winner) and a Mike Douglas (the talk show host). So he became Michael Keaton.

Asked about the phone book story, Keaton tells PEOPLE he’s not quite sure how he opted for the moniker that’s appeared on dozens of movie posters.

“I was looking through — I can’t remember if it was a phone book,” says Keaton, 72, raising those famously expressive eyebrows at times as he talks. “I must’ve gone, ‘I don’t know, let me think of something here.’ And I went, ‘Oh, that sounds reasonable.’”

And while the name “Keaton” has served him well, he’d like to go back to using a hybrid of his birth name and stage name — Michael Keaton Douglas — on professional projects.

He intended to do it on his most recent directorial effort, Knox Goes Away, a dramatic thriller released earlier this year, but he “forgot” amid the stress of making the movie.

“I said, ‘Hey, just as a warning, my credit is going to be Michael Keaton Douglas.’ And it totally got away from me. And I forgot to give them enough time to put it in and create that. But that will happen,” continues Keaton, whose name appears as Michael Keaton in his latest movie, Beetlejuice Beetlejuice, the follow up to the hit 1988 comedy Beetlejuice.

In the cover story, Keaton — who also appears in the drama Goodrich, out in October — reflects on his rise from humble beginnings to movie star.

The youngest of seven children born to George Douglas, a civil engineer, and Leona, a homemaker, Keaton says his childhood spent in the Pittsburgh suburbs was “fantastic,” even though his parents had modest means.

Keaton, who roughhoused with his brothers and watched Westerns on TV, knew as a kid he could captivate a crowd.

“I was always entertaining. Because when you’re the youngest, you have a built-in audience. And they were receptive,” he says. “I realized I could make people laugh and get out of trouble or get into trouble.”

It wasn’t until he dropped out of Ohio’s Kent State University as a young man that he began acting in earnest.

He landed a part in a local production of David Rabe’s dark comedy Sticks and Bones, and a newspaper critic took notice. “Someone said, ‘Hey, nice review.’ I had no idea what he was talking about,” recalls Keaton.

It would take several years of odd jobs— including breaking down sets and lighting shows at a PBS station for $2 per hour — before Keaton got his break in the 1979 sitcom Working Stiffs opposite Jim Belushi. It was canceled after one season.