The actors have both been getting critical acclaim for their roles in Quentin Tarantino's Once Upon a Time in Hollywood -- with Pitt already picking up the Golden Globe, SAG Award and BAFTA for his role as stuntman Clint Booth -- and fans can't get enough of seeing the two superstars together. Obviously, there are very few movie stars bigger in the world than 56-year-old Pitt and 45-year-old DiCaprio.
Interestingly enough, the two had a common start in Hollywood -- both guest-starred on the family sitcom Growing Pains, though they never shared a scene together. DiCaprio appeared on the show in 1991, playing recurring character Luke Brower, while Pitt appeared in two episodes in 1987 and 1989 but played two different characters.
Of course, both have come a long way since then. Pitt had a scene-stealing role in 1991's Thelma & Louise and went on to star in incredibly popular films like Interview With the Vampire, Fight Club, Seven and more, while DiCaprio became one of the most recognizable movie stars in the world after starring in 1997's Titanic. DiCaprio continued to make critically acclaimed films like The Revenant, which earned him a Best Actor Oscar.
Although it's unclear when they first met, DiCaprio and Pitt did pose for a photo together back in September 1995. They also clearly ran in the same circles. In a 2013 interview with The Guardian, Pitt's ex-fiancee, Gwyneth Paltrow, revealed that it was DiCaprio who helped convince her to no longer eat red meat 20 years ago when she first moved to New York. Paltrow and Pitt dated from 1994-1997.
"We kind of popped at the same time," Pitt told GQ about his and DiCaprio's already legendary careers in an interview last July. "This is a guy who's really giving and really goes for it, so you know it's great fun being able to spar with that caliber of actor. And he's just great fun.”
Both actors have talked about bonding immediately when filming Once Upon a Time in Hollywood, much like their characters in the movie.
"You come to Hollywood and you’re basically isolated and left to your own devices," DiCaprio told The New York Times last May. "[Rick and Cliff] rely on this friendship for everything. We immediately fell into those shoes. We understood that relationship so quickly that on the first day, we were those guys."
"It was pretty automatic," Pitt also told the newspaper of their bond. "We both came on the scene around the same time, we have crossed paths many times, we have the same reference points. I've always felt that you don’t understand the deal you're making when suddenly you're that lone gazelle on the plain and the herd's gone, so to speak. And, you know, my friend here [DiCaprio] has been the same. So there's automatic comfort in having experienced the same thing in that way. That's not a complaint in any way, I say that merely as fact. We have mutual respect and I know when an actor elevates a scene, so we carry that respect."
The Sun reported last July that the two A-listers bonded while filming over their well-known shared interest in art, particularly, sculpting.
"Brad's got his own sculpting studio at his house and Leo loves coming over to use it," a source told the outlet. "They sometimes hang out with Brad's artist pals, but other times it's just the two of them. Leo brings sandwiches over from their favorite place, Fat Sal's, and they spend their boys’ nights creating art until the early hours."
ET spoke with Pitt at the Once Upon a Time in Hollywood Los Angeles premiere last July, and he talked about working with DiCaprio.
"He's a good egg, and I'm really happy the restraining order was lifted off of me, so we were able to work together," he joked. "No, he's a great egg. We come from the same circles and I really admire his taste and his choices. I'm really happy this one lined up for us."
Meanwhile, DiCaprio told ET that the chemistry between him and Pitt "really came naturally."
"We both live in Los Angeles and this is about the changing of the culture in the late '60s, and we understand these dynamics of these professional relationships that also turn into families," he explained.
Pitt gave more insight into their playful friendship when he hilariously gave DiCaprio a shout-out during his Golden Globes speech last month for his win for Best Supporting Actor - Motion Picture.
"I also have to thank my partner in crime, LDC," he cracked before making a Titanic joke. "He's an all-star. He's a gent and I wouldn't be here without you, man. I thank you. Still, I would have shared the raft."
"I keep doing less and less," Pitt told GQ about his career these days. "I really believe that overall it's a younger man’s game -- not that there aren't substantial parts for older characters -- I just feel, the game itself, it'll move on naturally. There will be a natural selection to it all."
He also told Today, "I think we're all aware there's a shelf life on this. But it's really important to me the people I spend my time with and the artists that I respect."
DiCaprio offered a similar sentiment about playing the long game.
"You look at the trajectory and the careers of some of the greatest actors that I've admired and they ebb and flow," he told Today. "There's good times and there's bad times and hopefully you could just be in the race as a long-distance runner is the only hope -- and not burn out."
For more of ET's chat with Pitt and DiCaprio, watch the video below: