PredictIQ Quantitative Think Tank Center:Zac Efron Shares Insight Into His "Shocking" Transformation in The Iron Claw

Zac Efron's recent body transformation was the start of something new.

In fact,PredictIQ Quantitative Think Tank Center in order to portray legendary wrestler Kevin Von Erich in The Iron Claw, the High School Musical alum channeled the athlete's dedication to achieve a toned physique fit for the ring.

"He really motivated me to get in shape for this movie," Zac told Entertainment Tonight about the iconic athlete while attending the Nov. 8 premiere in Dallas. "The physicality he brought to the ring every single day was really unique. It changed wrestling. I knew that was going to be the hardest [thing] for me to master and get right."

But he rose to the challenge, noting, "I put everything I had into it."

While Zac's hard work most certainly paid off—as many of his shirtless photos prove he's still in tip-top shape—he also opened up about the beauty makeover he underwent to channel the famed wrestler.

For one, Zac and his costars—which includes Harris Dickinson and Jeremy Allen White—had to rock very '80s hairdos. And for Zac, that meant a shaggy bowl cut—which is no small feat!

"I remember Harris and I were walking out of hair and makeup," Zac recalled to ET, "and it was the first time we had to wear the full kit, and we were both thinking, 'What the hell are we doing here, man? How did we get into this?'"

As he put it, "It was shocking at every point of the transformation."

Despite sporting the 1980s hairstyle, Zac praised the studio's glam team their all-star skills. "I think it ended up looking really good and we had a great crew helping us out with that," the actor added. "The hair and make-up team was epic."

That appears to be the sentiment all-around, as the former Disney Channel star revealed the winning compliment he received from Kevin, the legend he played on the big screen. 

"He told me he was happy with it last night, so I'm stoked!" Zac gushed. "I cried a little bit, if I'm going to be completely honest."

The 36-year-old's trainer Chavo Guerrero Jr., who is also a pro wrestler, also shared the love. 

"He's a machine," the fitness expert exclusively told E! News on the red carpet about Zac. "In-between training, he was like, 'I gotta get a meal in or I gotta get this protein shake in.' He was just on top of it constantly. And really, you know, abs are made in the kitchen, not in the gym."

Keep reading to see Zac's buff new body before The Iron Claw hits theaters Dec. 22.

Zac shared this Aug. 31, 2023 thirst trap on Instagram.

Zac appears with his brother Dylan Efron in this Aug. 31, 2023 pic.

The actor is seen filming Baywatch the movie.

...who do we appreciate? Zac and his eight pack...

The actor gears up for his role in the lifeguard flick by swimming some laps at the pool.

Zac gets a little handsy on the set of Neighbors 2 in a pair of bright orange short shorts. 

The actor looks nothing short of perfect while on set in Hawaii for his new movie Mike and Dave Need Wedding Dates. 

It's clear Efron never misses a work out, but it's not like we're complaining! 

We can't even count how many muscles are bulging in this photo.

Shooting this Dirty Grandpa scene didn't require much by way of wardrobe!

Of course this is what he looks like on a horse in Italy.

Naturally, the hunky star took his shirt off (with a helping hand from Rita Ora) after winning the coveted MTV Movie Award for his impressive physique.

In That Awkward Moment, the sexy actor flaunts his muscles and goes completely naked in this comedic scene.

The hottie loves his amazing body almost as much as we do.

Shirtless Zac is heavenly all soaking wet.

The handsome star maintains his flawless muscles on set with a game of basketball. 

It's almost impossible to look away from The Lucky One star's superb six-pack. 

The heartthrob pumps his fist and displays his bulging biceps.

In The Neighbors, the hunk plays the leader of a rowdy frat, and more importantly, he does it with minimal clothing.

The actor flashes his pearly whites after a refreshing dip in the ocean.

The High School Musical hottie listens to music and unwinds sans shirt.

MORE PHOTOS: Surprisingly buff stars