The official Avengers: Endgame premiere is almost upon us, with the movie set to hit theaters as soon as April 24th in some markets, a full two full days ahead of the official April 26th release date. That means you only have a few days left until all the Endgame secrets will be revealed to you. It also means that you have a few more days to learn all sorts of new Avengers 4 spoilers, or do whatever it takes to avoid spoilers… like the one Chris Evans just dropped without anyone realizing it. Needless to say, you should stop reading right now if you want to be surprised when you go see the movie, as some major spoilers will be discussed below.

The Avengers cast and crew have been touring the world for the last few weeks as part of the final Endgame marketing push ahead of the film’s arrival. We’ve already seen plenty of interviews featuring the original Avengers from their press tour, as well as the official press conference that kickstarted it all. Some of these interviews were on the serious side of things, while others, like Stephen Colbert’s Just One Question: ‘Avengers: Endgame’ Edition, were on the funny side of things.

The gist of the Colbert segment was that various crew members of The Late Show with Stephen Colbert would ask the Avengers just one question. Most of the exchanges were hilarious, but we also have a huge spoiler in the clip, and it was disguised as a hilarious response.

When somebody asked who is the Avengers’ biggest enemy, most people gave the obvious — and quite boring — answer: Thanos.

Evans, meanwhile, spiced things up by saying that “honestly, I’d say chafing, if you’ve ever run through an interdimensional portal wearing a skin-tight body suit.”

Marvel fans aware of the various Endgame theories out there will quickly draw a link between what Captain America just said on TV, and all the theories that suggest the only way to beat Thanos was to go back in time using the Quantum Realm technology that was heavily featured in the last Ant-Man and the Wasp film.

We know the Quantum Realm will play a big role in future of the MCU, including Endgame, because we saw that confirmed in previous Ant-Man coverage. The white suits are likely meant to be used to travel through a Quantum Real portal that may be built by Tony Stark, Bruce Banner, and Scott Lang.

On top of that, we have a couple of scenes from the trailers that already suggest the Avengers went back in time — and the only way to do it without access to a Time Stone is the Quantum Realm. Past leaks have also pointed out that Marvel shot Captain America scenes set in the ‘40s or ’50s, and the film’s IMDB page mentions characters from scenes that take place in the ’70s.

So, while Evans made a joke about interdimensional travel for Colbert’s segment, he also accidentally slipped up and revealed a pretty big spoiler for the movie’s time travel action. That said, Evans’s revelation is easy to overlook if you’re not paying attention because this isn’t a serious interview. You can watch the full clip below.