Warning: Major spoilers ahead for "Avengers: Infinity War."

The cast of Marvel's "Avengers: Infinity War" clearly had more slip-ups when it came to spoilers than anyone realized. After video resurfaced showing Mark Ruffalo accidentally spilling the beans last year, now fans are sharing a clip of Tom Holland ruining his character's death on the movie's opening night.

Last Thursday, Holland and a group of the cast and producers/directors surprised fans at the first public showing of "Infinity War" at the Los Angeles Arclight theater. A woman named Claire (@foxdragonnred on Twitter) captured the moment on video and shared it to fans.

"I'm alive!" Holland yelled as he walked on stage.

The young star apparently thought he was surprising a theater full of people who had already seen the movie, and would therefore know that his character Peter Parker disintegrates and dies at the end of the film (along with half the galaxy's population). He thought he was providing them with the relieving sight of his healthy, happy face on stage.

Megan Amram, one of the writers of NBC's "The Good Place," tweeted that night about Holland's mishap.

Then Claire shared the video of the spoiling a few days later. Around one minute into the video (below), Holland is introduced. Marvel executive producer Kevin Feige, and the "Infinity Wars" directors Joe and Anthony Russo are already on stage.

The only thing Holland says when he first gets out in front of the crowd is: "I'm Alive!"

Then Benedict Cumberbatch is introduced and comes on stage. At this point, it seems to occur to Holland that he might have goofed.

"Did you guys already see the film, or are you just about to watch it?" he asks the crowd.

Amid the yells, he realizes they're all about to watch "Infinity War."

"You haven't SEEN it?" Holland says, and then immediately puts his hand on his face in a recognizable gesture of "oh no."

It's slightly ironic that Cumberbatch wasn't next to Holland when he let this spoiler slip. As another Marvel fan noticed, Cumberbatch and Holland have been paired for most of the "Infinity War" press tour. And since Holland is notoriously bad at keeping secrets, Cumberbatch operated almost as a "chaperon" (in his words).

You can see this play out in a compilation of Cumberbatch stepping in to prevent Holland from saying too much:

At least Cumberbatch was able to keep most of "Infinity War" secrets under wraps, even if the crowd at last Thursday's showing fell victim to Holland's spoilery nature.

This also isn't the first video to surface showing an "Avengers" star making a big mistake. You can watch Mark Ruffalo accidentally reveal that a lot of people die at the end of "Infinity War" here.

We're sure Holland remains in the good graces of Marvel fans, though. Even if his death was spoiled, it was one of the most emotionally resonant moments of the movie (a fact made even better by the revelation that he improvised those lines of dialogue).

Plus, most people should realize by now that Spider-Man's death isn't permanent. We know — thanks to more spoilers from Holland — that he's signed up to play Peter Parker at least two more movies. For more on why those disappeared characters will likely return, read INSIDER's full breakdown of the cliffhanger "Infinity War" ending.