Another superhero squad is joining the fight to save the world. A new teaser for Avengers: Doomsday features the X-Men, marking the first time the faction of mutants will team up with the folks currently populating the Marvel Cinematic Universe (MCU).

The minute-long teaser features Patrick Stewart as Professor X, aka Charles Xavier. "Death comes for us all. It's all I know for sure," he says in the trailer, which features moody footage of Xavier's School for Gifted Youngsters. "The question isn’t 'Are you prepared to die?' The question is 'Who will you be when you close your eyes?'"

The teaser reunites Professor X with Magneto, aka Erik Lehnsherr (Ian McKellen) and also reveals another superhero: James Marsden’s Cyclops, aka Scott Summers, who is seen battling what appear to be sentinels as his signature red beams shoot from his eyes.

The characters featured in this X-Men teaser were introduced in 2000 with Bryan Singer's X-Men, which was then followed by 2003's X2 and 2006's X-Men: The Last Stand. The franchise also launched spin-offs, such as a trilogy about Hugh Jackman's Wolverine, as well as a series of prequel films.

The original X-Men films were produced by 20th Century Fox and Marvel Entertainment. Disney acquired Marvel in 2009 before acquiring 20th Century Fox in 2019. This allowed for the world of X-Men to be incorporated into the MCU, starting with Deadpool & Wolverine. Doomsday will be the first time we see the Avengers join forces with the X-Men.

Fans were particularly thrilled to see Marsden in action in the teaser. One wrote in the YouTube comments, "James Marsden finally getting the Cyclops moment he deserved 20 years ago. That optic blast was INSANE." Another added, "Cyclops got more justice in 1 minute then his entire run in fox."

The X-Men aren’t the only intriguing superheroes headed to the big screen for Avengers: Doomsday. Chris Evans's Steve Rogers, formerly known as Captain America, is joining the fight against Doctor Doom, played by former Iron Man star Robert Downey Jr. A new teaser also revealed that Chris Hemsworth's Thor will be back.