Austin Butler was given some unconventional prep material while gearing up for his upcoming baseball-flavored crime thriller, “Caught Stealing.”

In a new cover story for Men’s Health released Tuesday, the “Elvis” star shared how director Darren Aronofsky provided him with a plethora of photos of MLB players’ backsides so he knew just how to bulk up for his role as a former ballplayer caught in NYC’s gritty crime world.

“I actually have a whole section of just baseball players’ asses that he would send me,” Butler told the magazine. “He was like, ‘Look how thick they are!’ ”

In addition to putting plenty of time in the gym, the actor told the magazine that he helped himself flesh out his 150-pound frame with a hearty diet of pizza and beer.

Baseball players’ derrières have been earning a curious amount of attention as of late.