Mark Ruffalo Totally Ruined The Ending Of 'Infinity War' Last Summer, And Everyone Thought He Was Joking

*SPOILER ALERT - This article reveals crucial plot points from Avengers: Infinity War*

If you're an actor in a Marvel movie, you sometimes have to keep huge, important secrets for years while the world begs you to let them in on the tiniest little spoiler. It turns out that last summer, Mark Ruffalo accidentally spilled the beans about Infinity War's terrifying finale. In the moment, the actor (who portrays Bruce Banner/The Incredible Hulk) managed to play it off like a joke, but eagle-eyed observers may have noted a touch of genuine fear in co-star Don Cheadle's voice as Ruffalo revealed the actual ending of Marvel's biggest movie.

Here's the clip from July of last year:

Cheadle and Ruffalo both played the moment off as a joke, but for one terrifying instant, they both knew Ruffalo had stepped over a line.

Fortunately, fans thought it was all just a classic Ruffalo bit!

But it turns out the truth was a lot harder to deal with.

Who knows what else Ruffalo has said in the past?

There's no denying that, with the benefit of hindsight, the clip is an especially tense one.

The next time you see The Hulk giving an interview, it may pay to give him your full attention. One never knows when the truth might accidentally slip out!

H/T - Twitter, Vox