King of Marvel spoilers Mark Ruffalo is at it again, letting slip that Spider-Man will be "fighting an alien in the future"

Mark Ruffalo is at it again. Marvel's resident king of spoilers may have just let another secret slip – and, this time, it concerns Spider-Man.

"I promise you, one thousand percent, that he will be fighting an alien in the future," the actor, who plays Bruce Banner/Hulk, said during a recent appearance at the Cinema Adriano in Rome, Italy.

Some fans have taken this as confirmation that alien symbiote Venom will appear in Spider-Man: Brand New Day, something that's been whispered about for a while now. "Spider-Man fighting Venom confirmed???" is the caption on the video, but others think he's "trolling."

"Well technically he already fought an alien, Thanos," someone else pointed out.

Either way, Ruffalo is well-known for letting the cat out the bag when it comes to MCU secrets. Most infamously, he revealed that half of the universe would die in Avengers: Infinity War before the movie had been released, spoiling the Thanos snap twist.

More recently, he hinted that he would appear in both Avengers: Doomsday and Avengers: Secret Wars, despite being on the cast list for neither, and that his Marvel co-star Chris Hemsworth would also return for Secret Wars.

We know a lot more about what to expect from Tom Holland's next outing as the web-slinger thanks to the first Spider-Man: Brand New Day trailer, but plenty of things are still under wraps. For one thing, Sadie Sink's role is still a secret, although we have plenty of theories…

Spider-Man: Brand New Day arrives in theaters on July 31. In the meantime, get up to speed with the rest of Marvel Phase 6 with our guide to the other upcoming Marvel movies and shows.