Zac Efron felt "terrified" of playing a pro wrestler in 'The Iron Claw'.

The 36-year-old actor played Kevin Von Erich, a retired professional wrestler, in the Sean Durkin-directed movie - but Zac has admitted to feeling nervous before filming began.

Zac told 'Extra': "It’s really fun to push yourself into those things like initially, you know, Sean Durkin came to me for that role … I was terrified and I just committed to it and it paid off so I think it’s just a reminder to trust the process and stay hungry.

"There’s art to be made out here and people are still hungry for it so I’m really proud of the film."

Zac's performance has even earned praise from John Cena, who has been signed to the WWE since 2001.

The wrestler-turned-actor shared: "He did fantastic. He’s been getting a lot of great reviews and that’s honest from one person who’s been on the canvas and has been through a hell of a lot of matches. It was a fantastic performance.

"You encapsulated a moment in time that completely defined the wrestling scene in Dallas, Texas. It was just extremely well done."

Zac embarked on a gruelling fitness plan in order to star in the movie.

The Hollywood actor previously admitted that he relished the physical challenge.

Zac told Deadline: "The physical preparation and the training, that’s something that I’ve always found very interesting. I’ve always admired people’s transformations, in particular for movie roles. I just find that dedication fascinating and special when I see it."

The actor ultimately found the wrestling scenes to be "fun".

He said: "I felt like I was physically there; I felt mentally there, as a direct result of the training, and then from there, the wrestling, surprisingly, was fun."