The 48-year-old gushed about his acting idol in the Fault magazine's Winter 2013-2014 issue, saying, "I like Tom Hardy's balls. I mean not literally, I've never seen Tom Hardy's balls, just for the record."
He added, "We worked together in Black Hawk Down and he's a gamer, he's always up for it, he's fearless and he's really fun to watch as well."
But Hardy isn't the only one that Piven admires. He explained how Javier Bardem also ranks high in the list of actors he loves.
"He never lets you down," the Entourage star told the magazine. "He's a complete and utter inspiration."
And if Piven had his pick of who to work alongside of in Tinsletown, he revealed that he would "love to mix it up with Idris Elba."
He shared, "I'd love to work with Idris really in anything."
But Piven's currently hard at work on his hit British television show, Mr. Selfridge.
So what can fans expect to see in the upcoming season of the period drama?
"The backdrop is the First World War and some have to go off to war and we get to see the ripple effect throughout," he revealed.
"I think the writers and everyone did a beautiful job of showing that this season. There are new characters and they all intertwine beautifully and seamlessly."