Robert Downey Jr. Says Returning X-Men Stars ‘Lit Up’ the ‘Avengers: Doomsday’ Set

Robert Downey Jr. is returning to the Marvel Cinematic Universe in a significant way. While he steps into the role of Victor von Doom for the upcoming Avengers: Doomsday, he recently shared his reaction to working alongside legacy cast members from the original X-Men films. During a group interview at San Diego Comic-Con, Downey noted that the arrival of Rebecca Romijn and Kelsey Grammer created immediate energy on set. The cast members present, including Chris Evans and Pedro Pascal, expressed genuine enthusiasm for the crossover project.

Marvel has confirmed that Romijn and Grammer will reprise their roles as Mystique and Beast. The film serves as a massive junction point for the studio, bringing together the Avengers, the Fantastic Four, and various mutants. While details regarding plot interactions between Doom and the X-Men remain private, the atmosphere during production suggests a distinct convergence of different cinematic eras.

For the actors involved, this reunion carries historical weight. Rebecca Romijn noted that the process of becoming Mystique is faster during this production than it was in the early 2000s, though she credits the original makeup process for helping define the physical performance. Kelsey Grammer expressed a continued interest in the character of Hank McCoy, specifically citing the nobility and moral principles that define the character. He views these traits as central to the appeal of Marvel heroes in challenging narratives.

Beyond Romijn and Grammer, the production features several other original X-Men actors. James Marsden, Patrick Stewart, Ian McKellen, and Alan Cumming are all set to appear. These inclusions bridge the gap to the original X-Men film released in 2000. Marvel Studios schedules the theatrical release for Avengers: Doomsday on December 18, 2026.