Zac Efron Says “Iron Claw” Costars Pranked Him by Singing “High School Musical” Songs on Set: 'Fun Days'

Efron and his costars Jeremy Allen White and Stanley Simons shared some behind-the-scenes details at a screening for the wresting film on Sunday

Zac Efron appreciates a good laugh, even when the joke is on him.

During a screening and Q&A on Sunday for The Iron Claw at the Academy of Motion Picture Arts & Sciences' Samuel Goldwyn Theater in Beverly Hills, the actor revealed that he took some on-set pranks in stride.

When costar Stanley Simons shared that he "was singing some High School Musical songs" to poke fun at Efron's 2006 breakout role during downtime, the star admitted that it was one of the "most fun days."

"God damn it, Stanley! I do remember that being one of the most fun days that we had," Efron, 36, told PEOPLE and other audience members at the Samuel Goldwyn Theater.

"Filming a house party could go one way or the other. It's a lot of people that are stuck in one room for many days, it can be kind of daunting. But this one was just electric. It felt like a high school party."

Related: Zac Efron Jokes His Ego Was Bruised Filming Iron Claw in a Speedo: 'This Is Magic Mike!'

Simons told PEOPLE on Sunday how memorable it was working with someone he grew up watching: "I sung [some of 'Breaking Free'] to Zac when I was playing my music scene. That was definitely a life experience that I'll never forget."

"When I was singing the song, he was like, 'Oh, you're not hitting it, you're not hitting it.' I was like, 'Oh,' and I redid it. And I think I did a good job!" he added.

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Related: Jeremy Allen White Says Zac Efron ‘Really Looks Amazing’ in ‘The Iron Claw’

"We really bonded and got to hang out," Simons said of their time making the biographical sports film. "When we got on set it just felt natural. They were really welcoming to me, not just my brothers but all the cast members. So it was a little nerve-racking, but they just were very open."

The Iron Claw focuses on the true story of the Von Erich brothers, who made history in the early 1980s in the world of professional wrestling. Despite being one of the sport's most famous dynasties, they faced a series of personal tragedies which have come to be referred to as the "Von Erich curse" due to the tragic deaths of five members of the family between 1959 and 1993.

Getting more serious about the real work in the wrestling film, Efron noted writer/director Sean Durkin's impeccable attention to detail and knowledge of even the most "obscure wrestlers."

"And with the detail in which he remembered things from the matches from his television set at home was amazing," Efron continued. "So him being able to recall these very specific moments meant a lot. And where it really came into play, I think a lot was with the physicality in the ring."

Jeremy Allen White shared a similar appreciation of Durkin's dedication at Sunday's screening.

"Our wardrobe department was so specific. Hair and makeup. We just had a really excellent team put together by Sean to make sure that everything was as accurate and detailed as possible," The Bear star said.

“Zac’s a maniac,” White told Esquire of his costar in May. “He’s so focused and knowledgeable on training, diet, all that. In terms of a physical transformation, I think he kind of blew us all out of the water. He looks really amazing in this thing.”

The Iron Claw is in theaters Dec. 22.

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