Harry Hamlin on How Psychedelics Led to First Acting Class – and His Surprising Ongoing Saturday Activity

Over five decades ago, Harry Hamlin's college plans took an unexpected turn when he got invited on a road trip "to one of the most magical places on earth," he says.

It was two days before registration for architecture courses at UC Berkeley, and he spent the night at a hidden compound with tree houses at La Honda, a redwood forest south of San Francisco.

As he and a few friends sat around the campfire, a Hells Angel came down the road and asked for a wrench. The biker proceeded to open up a pipe in one of the treehouses and pull out a pile of blue bills. Psychedelics. To express his gratitude, he gave Hamlin and each of his friends a blue pill.

"I began to see things in a different way and my curiosity was sort of turbo-charged," recalls Hamlin, 71, who later missed the first day of registration. "By the time I got there, a guy said classes had filled up but if I hot-footed it over to the drama department, I might be able to satisfy my requirements. I ended up in Acting 101. I never got back to the architecture school."

With two new projects in the new year — the new AMC series Anne Rice's Mayfair Witches (premiering Jan. 8) and the film 80 for Brady (opening Feb. 3), in which he plays a retired football champion and Jane Fonda's love interest — the actor has long enjoyed taking the unexpected route.

"I think the key to longevity is to always pursue the next impossible task as an actor because you can never be an expert in this," says Hamlin in this week's issue of PEOPLE. "There's always another challenge."

Duran Photography Harry Hamlin

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Over the course of a five-decade career, Hamlin has always kept it interesting — whether it was starring in the 1981 epic film Clash of the Titans or 1982's Making Love (the first gay love story from a major movie studio, which he was cautioned against doing) to playing suave attorney Michael Kuzak in LA Law and unsavory ad exec Jim Cutler in Mad Men, to founding TAE, an energy fusion company which began as a start up.

Back in the seventies, when he was offered a three-picture deal from Warner Brothers, he asked if they'd ever make him do a movie he didn't want to do.

"Absolutely not," was the response, but when the young actor asked that be put into writing, they refused and Hamlin walked.

"Sue Mengers, my agent, couldn't believe it and said, 'Obviously this kid doesn't want to be a movie star' and she wasn't wrong about that," he says.

Paramount Pictures Harry Hamlin in '80 for Brady'

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But what he did want was to take risks. It was with that mindset that he played the lead in Equus in 1975 at San Francisco's American Conservatory Theater, a role which required him to be naked on stage.

"They didn't have us rehearse taking our clothes off so the first time we took our clothes off was actually the first night on stage together," he recalls. "It was trial by fire."

"To have that experience as your first professional experience, nothing is going to scare you after that," he adds.

Alfonso Bresciani/AMC Harry Hamlin in 'Anne Rice's Mayfair Witches'

Still passionate about trying the unexpected, Hamlin takes acting classes every Saturday and is currently studying Shakespeare's King Lear.

"I've been studying at the Beverly Hills Playhouse on and off for 40 some odd years, and that class has now morphed into a new class at the Hudson Theater," he explains.

"My lifelong pursuit has been to try and untangle the Shakespearean roles that I've done and want to continue to do. The thing about Shakespeare is it's a big mystery and every play is a big mystery and you've got to figure out the key to get in — and unlock the mystery."

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"I'm just getting into Lear so to deconstruct this, and get to the point where I know what I'm doing with it, will probably take six months," he continues. "And then you have to memorize the play and then you spend another six months trying to figure out how to do it right."

Alfonso Bresciani/AMC Harry Hamlin in 'Anne Rice's Mayfair Witches'

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Along the twists and turns, Hamlin says "acceptance" is one of the biggest lessons.

"The idea of acceptance and allowing the universe to be what it's going to be, and accept that it is what it is. Otherwise, you'll spend your life trying to smash a square peg into a round hole," he shares. "I spent many years doing that so I decided to toss my hammer away and just accept things."

For more on Harry Hamlin, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribe here.