Mark Ruffalo accidentally spoiled Avengers: Infinity War's ending in most cringeworthy interview of all time

Tom Holland is often the Marvel star accused of being unable to keep a secret, but it was actually Mark Ruffalo that proved to be the weak link when it came to Avengers: Infinity War.

Yep, it was only one of the most highly-anticipated movies of all time, and Ruffalo went ahead and dropped a HUGE spoiler before people even had chance to see it.

It all started with an interview on Good Morning America, when Ruffalo appeared alongside co-star Don Cheadle to promote the upcoming Marvel movie.

Things started off well as the pair discussed their characters and how Ruffalo found it fun as the Hulk to 'smash' Thor, but Cheadle did find himself having to remind Ruffalo that he shouldn't give too much away.

When asked if he could just 'give them a little taste', Cheadle responded: "I wouldn't say too much... hey, it's your career."

It's good advice, which Ruffalo took and... immediately ignored.

He then proceeded to say: "Like every other Marvel movie, it doesn't end well for the superheroes."

He could have stopped there and kept things cryptic, but no. He continued: "Wait until you see this next one, everybody dies."

Ruffalo gave away a huge part of the plot. (Marvel Studios)

Cheadle attempted to interject, but by then it was too late. Even his attempts to backpedal proved futile, as he said: "Not everybody... no. Was that...? Can we rewind that part?"

Unfortunately, however, life isn't a movie, and we can't go back in time. The moment was out there, and it became a notorious moment in Marvel history with people still talking about it to this day.

Footage of the toe-curling moment was shared on Twitter this week, with one person writing: "This was the best time to be a marvel fan."

Another wrote: "He realized he was about to lose his job when Don Cheadle looked at him."

Cheadle was horrified at Ruffalo's comment. (Good Morning America)

Thankfully Ruffalo didn't lose his job as a result of the slip up, though Cheadle did later joke that he'd be barred from doing any press after that.

Speaking to Jimmy Kimmel after the initial interview went viral, Cheadle said: "I tried to stop him, you saw it. I was like 'I wouldn't say... a lot,' you know?...

"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.' He just messed the whole thing up!"

Ruffalo's revelation at least didn't stop people from going to see Infinity War, and it went on to gross more than $2 billion at the box office. So, it's safe to say it was still a success!