A connoisseur of starring in roles partially naked, he says, "You have to pick your moments for your shirtless scenes. If you are smart and if it's planned correctly, you can do what Sly Stallone used to do, which is knock out all the shirtless scenes in the first two weeks and then shoot the rest of the movie," he says.
"But it doesn't work out that way for me. Usually, it's, 'Zac. Shirt off!'" he says, clicking his fingers. "So, I don't command that kind of power yet."
Efron will continue acting sans shirt in the movie version of the '90s TV hit, Baywatch, currently shooting in Savannah Georgia. He plays Matt Brody, a lifeguard formerly played by '90s hunk, French actor, David Charvet.
What does Efron remember about Baywatch? "The main thing is that everyone had the hots for Pamela Anderson," he laughs. "And I was no different. My memories are just blurs from seeing it very late on TV."
The Rock takes over David Hasselhoff's role as head lifeguard Mitch Buchannon, and Kelly Rohrback, Swimsuit Illustrated model (and Leonardo DiCaprio ex-girlfriend) slips into the iconic red swimsuit as Pamela Anderson's CJ Parker.
Efron offers, "Our take on it is that it's going to be very fun and very different but at its core it's still going to have that sexy beach fun kind of spirit. We are lifeguards. We are the firemen of the sea. It's pretty cool."
Meanwhile, Efron is celebrating the 10th anniversary of his High School Musical debut. The unlikely phenomenon forged a career for Efron and then-girlfriend (on and off-screen) Vanessa Hudgens. They became instant celebrities and their heavily documented relationship was splashed across magazine covers around the world.
"For me, High School Musical represented love and being free to express who you are regardless of what people think, whether it's music or art or something people consider to be nerdy or not cool. I mean, who gives a f**k? Just be you. And that was very exciting. And we did it through song and dance. So, I look back on those days and cherish them. I remember that time as an enormous fun whirlwind. It set the stage for having an open mind and being free."
Efron says he'd be up to star in another musical. "I'd love it. I'm actively searching for one now," he says. "The only singing I'm doing now is in the shower. I sing everything. At the moment I am listening to Purple Rain and Prince right now just on repeat. And Drake's album came out, so I am trying to memorise all those lyrics."
He may not be singing in Bad Neighbours 2, but Efron is certainly busting some dance moves. "The funny thing is, from the point of High School Musical forward everybody thinks I can dance on cue. And I am not a great dancer," he confesses.
"I am a physical person so I learn things and over a period of time and I can pick up movements and learn skills relatively quickly. But that just comes down to co-ordination.
"But that didn't help me two nights before we shot the scene where I dance in front of a crowd," he explains referring to a pivotal moment in the movie. "There was no plan or dance routine so I called a buddy of mine, a choreographer who I worked with on Hairspray. He dropped everything and we just spent some time in front of a mirror doing a dance. So what you see in the film is what we ultimately did."
Along with High School Musical, Efron became an overnight sensation. I ask him how he looks back on how life has changed in 10 years. "Where to begin?" he muses.
"I am 10 years older and I have 10 years of hard work and fun and life under my belt. I think I am growing up, taking one day at a time. I am learning to really pay attention to the present moment," he says.
"That's the most important thing."
