Robert Downey Jr. Reveals How the Original X-Men Cast Reignited His Excitement on the ‘Avengers: Doomsday’ Set

Legacy castings carry a particular kind of electricity when longtime franchise veterans step back into roles that defined an entire generation of superhero cinema. Few upcoming Marvel projects have leaned into that nostalgia quite as heavily as the studio’s next massive crossover event, which has been slowly revealing just how many familiar faces are returning to the fold.

Robert Downey Jr., now stepping into the role of Doctor Doom after more than a decade as Tony Stark, has been candid throughout the film’s press cycle about how surreal it felt sharing a set with actors who helped define the superhero genre decades before the MCU even existed. That excitement became particularly evident when discussing two specific castmates whose return carries special significance for longtime fans.

Downey revealed that the original X-Men cast lit up what he described as a constellation of excitement on the set of ‘Avengers: Doomsday.’ Speaking during a post-Hall H interview at San Diego Comic-Con, Downey said having Rebecca Romijn and Kelsey Grammer back was a big moment, adding that he and his fellow cast members simply nerded out over their presence, calling the whole experience just incredible, according to Entertainment Weekly.

That reaction wasn’t limited to Downey alone. He specifically referenced the reaction of several other high-profile castmates in the room during the interview, including Lewis Pullman, David Harbour, Paul Rudd, Chris Evans, Letitia Wright and Pedro Pascal, suggesting the collective enthusiasm extended well beyond just the film’s new lead villain.

Romijn and Grammer originally starred in the early 2000s ‘X-Men’ trilogy as Mystique and Beast respectively, franchise roles that helped establish the modern superhero genre years before Marvel Studios launched its own cinematic universe. Their return joins fellow original ‘X-Men’ veterans Patrick Stewart as Professor X, Ian McKellen as Magneto, James Marsden as Cyclops, and Alan Cumming as Nightcrawler, all confirmed as part of the sprawling ‘Avengers: Doomsday’ ensemble.

That reunion marks a significant creative choice for Marvel Studios, deliberately blending its own established roster of Avengers, Fantastic Four, and Thunderbolts characters with actors whose superhero legacy predates the MCU entirely. Downey’s comments suggest that novelty wasn’t lost on the cast itself, treating the mash-up as something genuinely thrilling to witness firsthand rather than just another day on set.

While Downey avoided revealing specific plot details, he did hint that Romijn’s Mystique factors into a significant moment involving Florence Pugh’s Yelena Belova, describing it as a big deal without elaborating further on how that confrontation plays out. That kind of teased-but-unconfirmed detail has become a familiar pattern throughout the film’s promotional cycle, with cast members offering just enough to generate speculation without spoiling the film’s tightly guarded story.

The film’s massive ensemble also includes stars from across the Avengers, Fantastic Four, and Thunderbolts corners of the MCU, positioning ‘Avengers: Doomsday’ as one of the most ambitious character crossovers the studio has attempted. Given how much star power the film is bringing together, Downey’s genuine enthusiasm about specifically sharing scenes with the original X-Men cast speaks to just how much weight this particular reunion carries within the broader ensemble.

With the film continuing to build anticipation ahead of its release, moments like this one offer fans a genuine sense of the atmosphere on set, one apparently defined as much by fan excitement among the cast themselves as by the scale of the production surrounding them.

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