Video: Ian McKellen and Patrick Stewart Reunite in AVENGERS: DOOMSDAY Teaser

Magneto and Professor X are back in a new teaser trailer for Avengers: Doomsday, the highly anticipated title from the Marvel Cinematic Universe. The video is the latest in a series of new promos from the forthcoming Avengers movie, which will hit theaters on December 18.

In the trailer, stage veterans Ian McKellen and Patrick Stewart return as the iconic mutant characters, reprising their roles from the X-Men films. "The question isn't: 'Are you prepared to die?'" McKellen poses in the video. "The question is: 'Who would you be when you close your eyes? '" This new film marks the first time the real-life friends have played the characters together since 2014's X-Men: Days of Future Past.

The trailer also offers a first look at James Marsden, who reprises his role of Cyclops. Though not featured, other confirmed X-Men stars include Tony winner Alan Cumming as Nightcrawler, Kelsey Grammer as Beast, and Rebecca Romijn as Mystique.

The star-studded cast also includes Chris Evans, Chris Hemsworth, Vanessa Kirby, Anthony Mackie, Sebastian Stan, Letitia Wright, Paul Rudd, Wyatt Russell, Tenoch Huerta Mejia, Ebon Moss-Bachrach, Simu Liu, Florence Pugh, Kelsey Grammer, Lewis Pullman, Danny Ramirez, Joseph Quinn, David Harbour, Winston Duke, Hannah John-Kamen, Tom Hiddleston, Channing Tatum, Pedro Pascal, and Robert Downey Jr. and more. Take a look at our guide to the stage stars in the film here.

McKellen is an acting luminary whose career on the stage has spanned decades, playing major Shakespearean roles from Macbeth to Hamlet to King Lear. He won a Tony Award in 1981 for Amadeus and is also the recipient of six Oliviers. Likewise, Stewart has interpreted Shakespeare in London and New York, winning two Oliviers (out of five nominations) and a Tony nomination. He has also received acclaim for his one-man version of A Christmas Carol.