Many celebrities loved Game of Thrones when the hit HBO series was dominating the small screen —  even former President Barack Obama requested (and got) early episodes. But, outside of Ed Sheeran, high-profile cameos were almost nonexistent in the fantasy show. That said, while shooting one infamous battle during the show's fourth season, one movie star reportedly tried to photobomb the proceedings from his yacht: Bruce Willis.

Wait, what? Did that really happen? According to James Hibberd's new oral history Fire Cannot Kill a Dragon: Game of Thrones and the Official Untold Story of the Epic Series... maybe. When filming "The Mountain and the Viper" in the Croatian city of Dubrovnik, there were tons and tons of yachts in the sea behind the climactic battle taking place between Hafþór Björnsson's towering Mountain and Pedro Pascal's wily Oberyn Martell.

"When we scouted the amphitheater, there were all these yachts out front," said episode director Alex Graves. "So we needed to make a deal to make sure the yachts weren’t there when we filmed. They all backed off a quarter mile so they wouldn’t be in the shot. Everyone agreed to do it — except one person."

That person, according to "multiple people working on Thrones," was action star Bruce Willis, who apparently didn't just refuse to move his yacht, but sailed it back and forth in front of the amphitheater in a fit of "yacht rage" to try to disrupt production.

"[The yacht] circled trying to say, 'F*** you, I’m in your shot,' a couple of times and we were all laughing because we were aimed away from the water at that time anyway," said Graves. Others aren't so sure it was Willis. 

Executive producer Bernadette Caulfield said, "I think that’s been blown up a little bit more than it probably really was. We never actually saw Bruce."

But Jon Snow actor Kit Harington did throw some shade in a 2019 interview with Variety, saying, “I don’t want to be Bruce Willis and be an action hero.” That's awfully specific for someone that DIDN'T try to get a yacht in the shot.

Could Bruce Willis' yacht have been more disruptive than the infamous Game of Thrones Starbucks cup?

Fire Cannot Kill a Dragon is out in bookstores now.