It’s one thing to train someone to look like a superhero if they start off with Herculean genetics. But to take a guy from normal-looking to Rock-like in a few short months—drug-free? That’s the Holy Grail of fitness.

Over 20 years in the business, L.A.-based trainer Patrick Murphy has pulled off just this feat with dozens of stars, including the once-skinny Tobey McGuire and the formerly-doughy Jason Segal. His most impressive accomplishment, though, was morphing Zac Efron into the guy who stood shirtless next to Dwayne-freakin’-Johnson in 2017’s Baywatch—and held his own.