Appearing Saturday at Comicpalooza in Houston, Texas, Holland explained how he accidentally spoiled the Marvel Studios blockbuster in front of studio chief Kevin Feige and Infinity War directors Anthony and Joe Russo.
"I was with Kevin Feige, the Russo brothers, and the whole team at Marvel, and what they do is they rent a party bus the night the film comes out and they drive around LA, going to different screenings, to introduce the movie or to talk about the movie afterwards," Holland said.
On the film's Friday night opening, the four went to a Los Angeles theater where Holland let slip his Spider-Man dies.
"We went to this screening and someone had told me before they had already seen the film, they've already seen the film," Holland said.
"So they give me a microphone and I walk on stage and I'm like, 'Don't worry, I'm still alive!' The whole audience look at me like, 'What the hell does that mean? What do you mean you're still alive?'" Holland recalled. "And then I look inside, Kevin, Joe and Anthony are like, 'Shut up, shut up, stop talking!' So opening night, I ruined the movie for about 300 people, so I'm so sorry for that."
Asked about next year's as of yet unnamed Avengers 4 and the soon-to-shoot Spider-Man sequel with more Spidey on the way, Holland said coyly, "Is there, though? Is there?"
Then, laughing, "There better be [more Spider-Man], there definitely better be."
Despite the in-the-works Spider-Man 2, Holland admitted he knows what's in store for the Marvel Cinematic Universe about as much as anyone else.
"I actually know nothing about the future of the MCU, clearly because I spoil everything," Holland said. "So I have faith [there will be more], but I don't know."
"And me more so than anyone else. On Avengers, I knew nothing," he explained.
"I saw a great meme the other day like, 'Why does Peter Parker look like he showed up to the wrong set?' I genuinely felt like that," the Peter Parker star said to laughs.
"I'm like, 'I'm in space! How did I get here'? So yeah, honestly, I didn't really know much at all, which is quite fun. Like you guys, I'm a huge fan of these movies, so being able to go to the theater and enjoy it as a fan — because I knew nothing about it — was great."
Holland will reprise his role as Peter Parker/Spider-Man in the yet to be named Infinity War and Spider-Man: Homecoming sequels, out May 3 and July 5, 2019, respectively.