'Magnum, P.I.' and 'Blue Bloods' star Tom Selleck writes memoir he calls 'You Never Know'

HOLLYWOOD (KABC) -- Tom Selleck is one of Hollywood's most familiar faces with a career spanning more than 50 years.

He became a television super star decades ago with the success of "Magnum, P.I."

Selleck has just added something new to his resume: author. He's written a memoir he calls "You Never Know."

The book includes the story of his unlikely career in show business, after growing up in Sherman Oaks and attending Grant High, Los Angeles Valley College and USC. He titled his memoir "You Never Know" because he calls his career "accidental."

"I didn't plan any of this," Selleck said. "I never studied acting. I never, in school, I never did plays. I never wanted to be an actor. And through the sheer serendipity of growing up in the city where the business is, some unlikely events happened. And you never know, you know?"

Selleck writes about his early days being in commercials. In his first one, he takes a shower with Safeguard soap before running into Teri Garr and Penny Marshall.

He did a deodorant commercial, one for Close-Up toothpaste and a commercial with Farrah Fawcett for Dubonnet.

"I smile at all that stuff," he said.

The bulk of Selleck's book, though, is dedicated to the "Magnum" years and everything that meant.

"It's not a play-by-play of 'Magnum' but it's what it's like having never had a regular job in the acting business to suddenly be the lead in a series and what goes on inside your head and what you do with the opportunity," Selleck said.

I had the opportunity to moderate a "Live Talks Los Angeles" Q&A with Selleck, where he reminisced with a theater full of fans and shared stories from the book, including his friendships with Carol Burnett, who did "Magnum" twice, and Frank Sinatra, whose last acting role was on the show.

When it came to sharing his stories, Selleck is a pretty private person, and he knew he wouldn't write a tell-all but he would share some of his own stories.

"So I had to draw certain lines," Selleck said. "But if you're going to do a book that's a memoir, you sure as hell better share with the audience what's going on inside your head."

His plan worked. "You Never Know" is now a New York Times Best Seller.