Marvel Studios has learned to keep a tight clamp on Hulk actor Mark Ruffalo's mouth because he's almost guaranteed to drop major spoilers. Case in point: Avengers: Infinity War star Don Cheadle was on Jimmy Kimmel, where he confirmed that Mark Ruffalo had indeed spoiled Infinity War's big twist ending before the film hit theaters.

As you can see in the clip above, Cheadle and Kimmel looked back at a segment from Jimmy Kimmel Live earlier in the summer, where Cheadle and Ruffalo were promoting Infinity War's release. During that segment, Ruffalo had “teasingly” spoiled the end of Infinity War by saying that “everyone” died at the end of it. However, when Cheadle and Kimmel looked back at the tape, it was clear that Ruffalo had let the actual ending to film slip.

“Well if you listen very closely, he actually started to say the absolute truth, and then had to try to say ‘everybody' after he almost said ‘half.' It was like, ‘You just messed the whole thing up!'” Cheadle says.

Despite Ruffalo's big faux pas, Cheadle says that there was no big fallout from Marvel — at least, “Not exactly.” The actor states that Ruffalo is not only done doing press tours for Marvel movies, but done doing any press for any movie, as he could look Marvel Cinematic Universe secrets. It sounds like he's joking when he says it — at least we think he is…

Ruffalo dodged a major bullet (maybe literally?) by having most press outlets run the story from the angle of him “jokingly” spoiling the end of Infinity War, with Cheadle seemingly in on the gag. A lot of fans thought Ruffalo was totally self-aware of his own image as a Chatty Kathy, and was playing that up for humor, but apparently, he really is just that aloof. According to the other Infinity War cast members, Spider-Man actor Tom Holland is Ruffalo's protege when it comes to letting the spoilers fly.

Needles to say, don't expect to see much of Ruffalo during the Avengers 4 press tour next spring.

Avengers: Infinity War is now available as a digital download and on Blu-ray and DVD. Ant-Man and the Wasp is now playing in theaters. Upcoming Marvel Cinematic Universemovies include Captain Marvel on March 8, 2019; Avengers 4 on May 3, 2019; Spider-Man: Far From Home on July 5th, 2019; and Guardians of the Galaxy Vol. 3 in 2020.