Awkward! Having Their Bodies Shaved Was First Step for 'Iron Claw' Hunks

Part of the process included the actors bulking up to look like their real-life counterparts. According to Variety, Dickinson gained 22 pounds and White packed on about 25 pounds of muscle.

"But nothing compared to Efron's Hulk-like transformation," Variety added. "I joke about it but it's true – I didn't want to stand close to him while shooting the movie because it would make me look my size," White said. "But it's hard because we play brothers. I do have to be around him. Although I tried to make Harris stand next to him most of the time."

Dickinson said, "I'm not naturally like a beefy guy. I'm a pretty skinny dude. You look at pictures of the boys and they're like big boys. So we just tried to eat a load and train and lift a lot of weight. I was immediately upping my calories to like 3,000."

Nor had any of the three ever set foot in a wrestling ring or known anything about its universe. This led writer/director Durkin to recruit pro wrestler Chavo Guerrero Jr. to train the actors and serve as the film's official wrestling consultant. Guerrero also appears on screen, facing off against Kevin as the Sheik.

"The actors were in the gym months before filming started, Guerrero grilling them on proper wrestling terminology and teaching them the nuances of a dropkick. They spent days just learning how to properly fall on their back, before graduating to flying leaps," wrote EW.

"We have some pretty funny iPhone footage of us seeing our wrestling for the first time," Efron told EW.

"I was like, 'Oh, that's what it looks like. Got some work to do,'" White said.

"The Iron Claw" will be released in theaters Dec. 22.