Going from a skinny teen idol to a shredded leading man is no easy feat—but Zac Efron has pulled it off better than almost anyone.

The June 2016 Men's Fitness cover star has turned himself into America’s favorite bro and he has the six-pack to prove it—watch any of his movies and at some point Efron will have his shirt off.

Changing the conversation about your career isn't always easy. So the star of Baywatch and Neighbors 2 went at it head-on, piling on muscle in the gym with intense training sessions of squat jumps, ab wheel rollouts, chinups, bicep curls, dumbbell Romanian deadlifts, mountain climbers, and much more to get down to just 5% body fat. By the end of it all, Efron had ripped abs, huge biceps, and a massive chest.

Much like his Baywatch co-star Dwayne “The Rock” Johnson—and these 24 jacked celebrity dudes—Efron enjoys showing it off on social media.

Here are 10 of his most jacked moments from Instagram:

10. Early morning wake-ups and workouts aren't just for Efron's Baywatch co-star:

 

Training like Teddy

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9. Proof that kettlebell workouts are a great way to go from skinny to shredded:

 

 #teamnosleep

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8. Efron flashes one of his biceps as he gets ready to hit the bike for a workout:

 

Inspired after watching #teamUSA

A photo posted by Zac Efron (@zacefron) on

 

7. Efron shows off his ripped six-pack and shoulders as he makes a "delivery" for his Baywatch co-star:

 

Special delivery for The Rock #Baywatch

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6. Better than flexing on the beach? Flexing underwater:

 

The last lifeguard is wrapped ;) #Baywatch

A photo posted by Zac Efron (@zacefron) on

 

5. Getting this jacked is no easy feat.

But you can pull it off, too. Efron told Men's Fitness about the workout and nutritional plan that got him there.

 

Honestly I have a hard time with paparazzi but s/o to this dude

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4. It's one thing to challenge The Rock to a tire flipping contest—it's another thing to try and beat him.

Efron puts his pecs and delts to the test as he attempts to pull off the victory on the Baywatch set. (Spoiler: He didn't win, but still makes it look good).

 

3. Efron doing his best American Ninja Warrior impression—and showing off his prodigious upper body:

2. Efron hitting the gym for back and biceps day:

Clearly those dumbbell curls are working.

 

Back and bi's #baywatch

A photo posted by Zac Efron (@zacefron) on

 

1. Zac finishing off a huge bench lift after a long day of filming:

 

Post filming chest/tri's. Now #GOT with Chicken/veggies #teamnosleep

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