Next year’s Avengers 4 is already generating seemingly endless rumors, from what the official title will be to which heroes won’t survive to see the credits roll.

One persisting rumor is that the Quantum Realm will play a major role in the movie. Between the Ant-Man and the Wasp‘s end credit scene and Tom Holland revealing that many of Benedict Cumberbatch (Doctor Strange)’s lines discuss the realm, many fans started speculating that the fictional other-reality realm will be an important plot element.

Speaking on On Air with Ryan Seacrest, Ant-Man and the Wasp actor Michael Douglas added even more support to the rumor when he called the Quantum Realm “the key” when he answered a question about how the Ant-Man movies will connect to Avengers 4.

“The Quantum Realm plays an important part in all the next chapters, I think, of the Marvel films,” he confirmed.

It’s unclear exactly how the Avengers may be able to use the realm to their advantage, but with half of the world’s population (super and otherwise) wiped out at the end of Infinity War, it seems like messing with time and space may be the only way the beat Thanos once and for all.