Borg vs. McEnroe, Janus Metz's film chronicling the unforgettable tennis rivalry between John McEnroe and Björn Borg, is out in select theaters and on-demand today. Shia LaBeouf stars as McEnroe, a role for which he's again earning widespread critical acclaim. Thursday night, LaBeouf joined Jimmy Kimmel on his show to discuss the creative process behind bringing such an iconic chapter of McEnroe's life to celluloid.

"There were two different McEnroes," LaBeouf said when Kimmel suggested he was the perfect fit for the role. "This was more of an in-depth study, like, into his psychology and the director got us together and we were on this boat in France and the French can be very forward. For instance, we're sitting there and I had put on a bit of weight for a different thing and the producer's like, 'Hey, you're playing McEnroe!' There's, like, maybe 10 people around and he's like, 'Oh, that's great, yeah, that's gonna be really good, but you're very fat.' And I thought there was maybe another way to get to that? In America, somebody would be like 'So what are you gonna do for prep?' None of that, man. The Danish people are just like 'Hey, you're really fat, man.'"

Though McEnroe and LaBeouf have never met him, LaBeouf said he has nothing but "big love" for him. "He knew it was happening," he said. "Busy guy. I don't know what the bureaucracy of it all was but nothing but love for John McEnroe, man."

When Kimmel said he felt like the tennis legend would enjoy the film, LaBeouf agreed. "It is really made as a testament to the relationship, but I think what he said was it 'makes me look like too much of a jerk,' so really, knowing McEnroe, that's like a glowing endorsement. So, thanks John."

At the end of the Borg vs. McEnroe portion of the chat, LaBeouf explained how the tennis sequences in the film (which required LaBeouf to play lefthanded) were captured. "We learned it like a dance," he said. "So, they would play a metronome. There's no ball, and we would just learn every single point, where every foot, every hand [is placed], and we would just study it like a dance. They would play a metronome and you would know when the ball was bouncing, so the crowd would know where the ball was and the player would know where the ball was based off audio cues."

Watch the interview above.