Warning: spoilers ahead. When Mark Ruffalo is around, a spoiler alert is necessary as he spoiled Avengers: Infinity War months before the premiere.

Ruffalo Reveals Who Dies In 'Infinity War'

In an interview at the Disney D23 Expo, Ruffalo accidentally revealed one of the most important twists in Avengers: Infinity War.

"Wait 'til you see this next one. Ha-Everybody dies!" Ruffalo tells the interviewer in the video posted by Good Morning America.

Fans who have seen the wildly successful Infinity War will note how the actor even nearly says "half" instead of "everybody," which is even more accurate to the film's ending. However, even as he spared the viewers that important detail, Ruffalo's spoiler is still a major one that's a large part of the film.

Costar Don Cheadle, who sat beside the actor, started at his fellow actor's words and exasperatedly chided at him, "Dude!"

"Not everybody, no," Ruffalo amends, scrambling to recover. "Can we rewind that part?"

The interviewer attempts to move the conversation along without acknowledging the major spoiler that the actor just dropped.

"Am I in trouble?" Ruffalo asks Cheadle. "Is Barry going to be mad at me? I'm sorry, man."

'Infinity War' Cast Has Spoilers For Everyone

With a massive cast of superheroes on board for Infinity War, there are bound to be a few spoiler-friendly cast members in the bunch. Ruffalo is one, but Spider-Man: Homecoming star Tom Holland is another.

According to a report from Comic Book, directors Joe and Anthony Russo, Marvel Studios boss Kevin Feige, and actors Benedict Cumberbatch and Holland appeared in front of a crowd at the Arc Light Cinemas to thank them for their support. While the appearance was brief, it wasn't brief enough to keep Holland from talking.

"I'm alive!" he yells to the crowd, referencing his character's tragic end in the movie.

Holland is known for spilling set secrets during interviews. In an appearance in Jimmy Kimmel with his other costars after the premiere — but before the public release date — he also revealed that his character will be in space, which is a major plot detail in Infinity War.

Sebastian Stan, who plays Bucky Barnes, completes Marvel's trinity of spoiler-prone superheroes, but the secret he spilled haven't made its way on the screen yet. The I, Tonya actor sat down with The Independent and talked about being in a massive scene with so many characters throughout the Marvel films.

"You look around and you just saw everyone from Samuel L. Jackson to Michael Douglas to Michelle Pfeiffer. Everybody was there," Stan describes.

Pfeiffer is a particularly surprising spoiler, considering her character The Wasp has disappeared into the Quantum Realm decades ago. The hero The Wasp is now taken over by daughter Hope, who Evangeline Lilly plays in Ant-Man and The Wasp.