Before Jack Gleeson became the cruel, evil King Joffrey on Game of Thrones, he was an uncredited kid in Reign of Fire — which was a movie about dragons, appropriately. During his spotlight panel at New York Comic Con on Friday (October 7), Gleeson was asked about his memories from set.

Besides referring to it as a "mediocre" film, he noted how his casting wasn't because of his acting abilities, but because the movie was filmed in Ireland, his birthplace. During his scene, he and a horde of fellow Irish kids watched Christian Bale and Gerard Butler reenact a pivotal moment in Star Wars: Episode V - The Empire Strikes Back. While filming, however, Gleeson was having some serious internal plumbing problems.

He recalled really needing to use the bathroom, but was told to hold it because they were shooting. Gleeson gave it the ol' college try, but eventually, his bladder had had enough. "I just kind of had to wet myself," he confessed. "I was like an 8-year-old or 9-year-old kid and I had to piss my pants on set of Reign of Fire." Gleeson later went on to joke that his peeing faux pas could be the reason he considered the film mediocre.

Gleeson was unsure whether anyone noticed his, um, situation. "I tried to be as cool and collected as possible," Gleeson said, "and then I acted my socks off. I didn't let it affect my performance." This inadvertently prepared him for moments on Game of Thrones, like exhaustion from filming and trying his hardest not to nod off during his post-death scene, as well as trying to figure out how it looked to choke to death without having actually experienced it himself.

You can check out Gleeson's scene below — and as you do, remember his bladder had betrayed him as this was unfolding.