On Tuesday, the talented trio stepped out for the U.K. premiere of their new film, Once Upon a Time in Hollywood, at Odeon Luxe Leicester Square, pulling out all the stops with their red carpet looks.
DiCaprio, clad in a classy three-piece suit, striped tie and leather shoes, shaded his eyes with a pair of Oliver Peoples sunglasses.
Pitt opted for a slightly more casual look, sporting some scruff and leaving the collar of his navy dress shirt unbuttoned.
Meanwhile, the always-fashioble Robbie stole the show once again, sporting stunning Chanel earrings, a gold metal Edie Parker clutch and a flowy, burnt orange Oscar de la Renta dress that featured a plunging neckline.
Robbie's makeup artist, Pati Dubroff, added an extra dash of glam, matching the actress' beauty look to her gorgeous gown with a sunset smokey eye, light mascara and rose lips.
After arriving at the premiere solo, DiCaprio, Pitt and Robbie posed together for a few pics on the red carpet. They were later joined by director Quentin Tarantino, along with fellow castmembers like Damian Lewis and Lena Dunham.
Once Upon a Time in Hollywood, in theaters now, also had a premiere in Los Angeles earlier this month, where Pitt explained what it was like working with DiCaprio in an interview with ET on the red carpet.
"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," Pitt joked of the fellow Oscar winner. "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."
"His character in this is hilarious," Pitt added. "He throws one of the best tantrums ever laid down on film."
Hear more in the video below.