WARNING: Contains spoilers for Avengers: Infinity War

Disney are notoriously strict about spoilers when it comes to Marvel movies. They often hold back press screenings to the last minute and publicly plead with fans not to reveal any secrets, but the one thing they can't seem to control is their own stars.

Just this week, Gwyneth Paltrow might have accidently dropped a bombshell about Tony and Pepper's future, which puts her in a long line of MCU actors who just can't keep their big mouths shut.

Look away now if you don't want to hear any MCU spoilers. And maybe avoid any interviews with Mark Ruffalo and Tom Holland too…

1. Mark Ruffalo spoils Avengers: Infinity War

This content is imported from Twitter. You may be able to find the same content in another format, or you may be able to find more information, at their web site. Uh oh, @DonCheadle, is @MarkRuffalo going to get in trouble with @MarvelStudios now!? #InfinityWar #D23expo pic.twitter.com/WR5C1QCBTb — Good Morning America (@GMA) July 16, 2017

The mother of all spoilers actually got leaked a full year before everyone else found out – and it was all Mark Ruffalo's fault. Getting a bit too chatty during a Good Morning America appearance alongside Don Cheadle back in July 2017, Ruffalo awkwardly dodged a question about the end of Thor: Ragnarok and somehow managed to blurt out the one thing Marvel probably didn't want him to say instead. "Wait until you see this next one," he laughs, "everybody dies!".

In hindsight you can quite clearly hear that he starts to say "half" before trying to turn it into a gag.

The crushed look on his face about two seconds later seems like punishment enough (as does Cheadle's look of utter disgust) but he immediately starts worrying about the repercussions of breaking whatever contract he's signed. "Is Barry gonna be mad at me?" he asks Cheadle, looking panicked.

Whether Barry is Marvel's lawyer, Disney's hitman, or Thanos' angrier younger brother, if the Hulk is scared of him, he's probably not someone you want mad at you.

2. Mark Ruffalo spoils Thor: Ragnarok

This content is imported from Twitter. You may be able to find the same content in another format, or you may be able to find more information, at their web site. Mark Ruffalo leaked a sneak peek of #ThorRagnarok from yesterday's premiere! pic.twitter.com/JE5VfmQMPY — Best of Marvel (@thbestofmarvel) October 11, 2017

Around about the same time he was spoiling the end of Infinity War, Ruffalo pulled a gaffe so huge it's a wonder Disney even let him out in public anymore.

Trying to be down with the kids, Ruffalo went on Instagram Live to stream his arrival on the red carpet for the premier of Thor: Ragnarok – and then forgot to turn the damn thing off when he put it in his pocket. Maybe he didn't know how to turn it off? Maybe he thought he took a photo instead of a stream? Maybe he got distracted by the free popcorn?

Whatever happened, thousands of fans were treated to the sound of him entering the building, taking his seat and watching the first 15 minutes of the film (after which, presumably, Barry found him).

3. Tom Holland spoils Spider-Man 2 and 3

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You can't really blame Tom Holland. Fresh from Spider-Man Homecoming, the then 20-year-old was understandably excited about the fact that he gets to play Peter Parker – and even more excited about that fact that he's signed up for a whole trilogy. A fact which hadn't been announced at the time.

"There is still a lot of room for Peter Parker and Spider-Man especially to grow in the next two movies," he told French site AlloCine at the time, with a big giddy grin on his face. "It's going to be an exciting couple of movies… Yeah, there'll be Spider-Man 2 and 3, it won't be Homecoming 2 and 3."

Immediately trying to make light of it, Holland apologies to the camera before pretending to get shot (by Barry).

4. Tom Holland spoils Avengers: Infinity War

This content is imported from Twitter. You may be able to find the same content in another format, or you may be able to find more information, at their web site. Thanks, @TomHolland1996. Thanks, @MarkRuffalo. @Avengers #InfinityWar (via @TomHolland1996's Instagram Live) pic.twitter.com/t0luvCyihS — Marvel Entertainment (@Marvel) November 28, 2017

Having learned from his mistakes on the press tour for Spider-Man Homecoming, Tom Holland kept his mouth shut during the lead up for Infinity War. Until Mark Ruffalo sent him the poster, that is (RUFFALO!!!), and he decided to open it on Instagram Live.

Showing the camera the contents of the envelope in close up, before turning it around to let everyone read the words "Confidential: Do not share", Holland's leak forced Marvel into officially releasing the poster on the same day to cover their backs.

"For the record Marvel, I didn't spoil this one." Tweeted Ruffalo, probably locked in a Disney dungeon somewhere. To be fair though, he sort of did, since he was the one who mailed it to Holland.

5. Tom Holland spoils Avengers: Infinity War again

This content is imported from Twitter. You may be able to find the same content in another format, or you may be able to find more information, at their web site. *Spoiler Alert*

@KevinFeige @Russo_Brothers @TomHolland1996 and Benedict Cumberbatch introducing Infinity War at @ArcLightCinemas Hollywood

Part 2 (the one where Tom spoils the movie) pic.twitter.com/OaW8HCTE91 — Claire (@foxdragonfilms) May 1, 2018

Admitting that he's not the best at keeping secrets, Holland revealed that he wasn't even shown a script for Infinity War – with directors Anthony and Joseph Russo only letting him see the scenes he was in. Unfortunately, he was in the very last scene of the movie, which contained the biggest secret of all.

Thinking it was safe to let him start talking to people about ten minutes before they watched the film for themselves, the Russos let Holland introduce the premiere on stage at the Arc Light cinema in Hollywood.

"I'm alive!" he yelled, literally as soon as someone gave him a microphone. He thought the audience had just seen the film. They hadn't.

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