Austin Butler's personal trainer put him through a gruelling workout regime and nutrition plan to take his body to the "next level"

Captioning a photo and video carousel featuring Butler flaunting his ripped, muscle-bulging body in a gym, Roy wrote: "When Austin came to me after wrapping Caught Stealing he saw it as the perfect moment to take his body and health to the next level.

"This wasn't just about prepping for another role, it was about building a sustainable foundation for long-term peak performance."

Roy pointed out he had "14 weeks" to prepare Butler, 34, for his upcoming crime film Enemies, as well as his recent shirltess cover shoot for Men's Health, which was released earlier this month.

He continued: "We had 14 weeks to get him ready for Enemies and just half that time to get him cover-ready for Men's Health.

From the start we agreed that becoming one of the greats is a long game.

"You can't sacrifice health and wellness every time a new aesthetically demanding role comes along."

The health guru promised the Elvis star that they would take a "different approach that prioritized strength and longevity"

Roy added: "We started our journey in April and the following images show what 14 weeks of smart, consistent work can do.

"We combined technical movement, whole-food nutrition, and timeless training principles not just to get him in peak shape, but to build habits that last a lifetime."

Concluding his caption, Roy gushed: "So proud of you @austinbutler."

As well as photos, the carousel also featured videos of Butler doing different exercises, including running, biking, weight-lifting and lunges.

Butler previously revealed that he almost cracked his rib shooting Caught Stealing.

The star - who plays Hank Thompson in the new crime comedy by Darren Aronofsky - filmed a scene where his alter ego gets "beaten" by two Russians, including Pavel (Nikita Kukushkin), and things took a very real turn during the shoot.

He recalled in a recent interview with Men's Health: "He [Aronofsky] put me through the ringer on this film. It's a lot of running away from people chasing me with cars and getting beaten up repeatedly.

"I get beaten up by these two Russians in this film. This one - Nikita, who's a short king - he's got so much power.

"When he was kicking me, he didn't want to kick me very hard. He felt bad and I kept telling him, 'Just kick me. Just kick me harder.'

"And there was the thing when I watch it back that it doesn't look real. So he starts really laying into me and kicking me hard.

"But then he had this idea of headbutting me in the side like a little ram or something. And he did it so hard it almost cracked my rib with his head.

"I was very impressed."