Selleck sat down with PEOPLE for this week’s cover story, where he discusses his new memoir, ‘You Never Know’

Tom Selleck’s signature mustache almost didn’t make it onto his CBS show Blue Bloods.

Speaking with PEOPLE for this week’s cover story, the actor, 79, reveals that he initially wanted to shave off his facial hair to step into the role of police commissioner Frank Reagan on the show, currently in its final season.

“At the time, they had him as the New York City police chief,” Selleck says of the role. “That’s not the boss in New York, the way it’s structured.”

“And I said, “Well, I don’t think they can have mustaches, so I’ll shave off my mustache,’” the actor continues. “And [executive producer] Leonard [Goldberg] said, ‘Let me check with CBS.’ And they said no.”

Selleck says that he was often asked to get rid of his ‘stache throughout the early days of his career.

“I just got used to it and used to have to shave it off for those early jobs,” he says. “And then it was kind of okay.”

While much of Selleck’s work — including his hit show Magnum, P.I, which earned him an Emmy, and the 1987 film Three Men and a Baby — featured his now-iconic facial hair stylings, he did shave it off for the 1997 film In & Out, in which he played reporter Peter Malloy, opposite Kevin Kline.

Selleck recalls that the film’s director, Frank Oz, had his own plans for his character’s look.
“[Oz] said, with the barber there, ‘Would you trim your mustache a little?’” Selleck says. “I said, ‘Sure.’ And then he said, ‘A little more than that.’ And then he said, ‘Well, would you shave it all off?’ I said, ‘Sure.’”

Selleck caught up with PEOPLE for this week’s cover story, in which he reflected on his decades-long career in film and TV ahead of the publication of his new memoir, You Never Know, out this spring from Dey Street Books.

“It is really the story of an accidental career,” he says of his acting beginnings, which kicked off with early appearances in commercials and on The Dating Show.

Selleck notes that his memoir, which took four years to complete, “is a lot about failing, endless failures,” and that despite its challenges, penning his story was ultimately rewarding.

You Never Know will hit shelves on May 7 and is now available for preorder, wherever books are sold.