Sylvester Stallone and Richard Gere clashed over Princess Diana years after butting heads on the “Lords of Flatbush” set.

Elton John wrote in his 2019 memoir, “Me,” that he invited the actors and the royal, among others, to a dinner party in the ’90s — and the Princess of Wales “straight away” seemed “taken with” Gere.

“She was separated from [now-King] Charles by this point,” the singer, 79, clarified, noting that Gere, 77, “had broken up with Cindy Crawford.”

Stallone, 80, allegedly took issue with the pair “sitting in front of the fireplace together, locked in rapt conversation,” with John claiming his husband, David Furnish, stumbled upon the Golden Globe winners about to duke it out in a hallway.

The duo were “apparently about to settle their differences over Diana by having a fistfight,” John wrote — and Stallone stormed out of the bash when Gere continued his flirtfest.

The “Rocky” star allegedly said, “I never would have come if I’d known Prince f- -kin’ Charming was gonna be here. If I’d wanted her, I would’ve taken her!”

Diana, meanwhile, was “completely unruffled” by the drama, according to John.

“Maybe she hadn’t realized what was happening,” the “Rocketman” hitmaker wrote. “Or maybe stuff like that happened all the time.”

Reps for Stallone, Gere and John did not immediately respond to Page Six’s requests for comment.

The dinner party took place around the time John was writing songs for the 1994 film “The Lion King.”

Two decades before the movie came out, Gere and Stallone clashed on the “Lords of Flatbush” set, the latter claimed in his “The Steps” memoir — so much so that “one of [them] had to go.”

“It was clear to everyone that this wasn’t working,” the “Rambo” star wrote in the book, published Sept. 29, of Gere being replaced by Perry King.

The men’s issues began during an ad-libbing audition moment, with Gere’s nails digging “into [Stallone’s] skin” when he grabbed his potential co-star’s tee.

“I told him to back off, but he did it again on the second take. He couldn’t have known, but Gere had begun to stir the emotional cauldron inside me,” Stallone recalled, adding that he asked director Stephen F Verona to “react the way [he] would actually react if someone did that to [him] in real life.”

When he clarified that this meant he would “knock [Gere’s] teeth out,” Verona replied, “Please don’t.”

They nearly brawled again when filming started and Gere had to insist he didn’t “want to get physical” when he angered Stallone by spilling chicken grease on him.

“The Steps” is available wherever books are sold.