His comments follow Ruffalo's now famous slip up back in 2017, in which he pretty much spoiled the ending of Avengers: Infinity War on Good Morning America - where he appeared alongside Cheadle.
The interviewer asked about the outcome of Thor:Ragnarok and Ruffalo asked Cheadle if he could reveal "a little". Cheadle said: "I wouldn't say too much, but you can say as much...I mean, hey, it's your career."
Ruffalo started to say that the ultimately "doesn't end well for the superheroes", then he added: "But wait until you see this next one! Everybody dies!"
Poor Cheadle nearly fell out of his chair exclaiming: "Dude! Dude! Dude!" and shaking his head while Ruffalo desperately tried to backtrack.
Catch the awkward moment here: