Jeremy Allen White is revealing one major influence on his buff transformation for the upcoming "Iron Claw" movie ... telling TMZ Sports his co-star Zac Efron helped whip him into wrestling shape!!
JAW is playing Kerry Von Erich in the project about the famous Von Erich family ... and while he was never in bad shape by any means, the dude really bulked TF up for the role.
In fact, he didn't shy from putting his swole figure on display ... dropping the top for a workout back in July.
Naturally, we had to ask JAW all about his new bod outside "Jimmy Kimmel Live!" this week ... and whether Efron -- who's always been chiseled -- motivated him in the gym.
"He definitely did!!" White said.
As for actually wrestling in the future, JAW ain't too sure he can hang with the big boys ... especially considering he was so fresh to the industry when he got the gig.
White added he has a ton of respect for professional wrestlers ... pointing out it's a super athletic sport, so all the haters who trash it due to it being "fake" should listen up!!