Robert Downey Jr. is confirmed to return to the Marvel Cinematic Universe (MCU) in 2026’s Avengers: Doomsday, but fans are now speculating that he might take on a dual role as both Iron Man and Doctor Doom. This unexpected twist has intensified discussions about the upcoming MCU Phase Six films, particularly how Downey Jr.’s involvement will impact the multiverse storyline.
Downey Jr. shared a glimpse of his reading material on Instagram, revealing that he has been studying comics like Secret Wars and Iron Man: Legacy of Doom. The former features a cosmic character called The Beyonder who pits Marvel’s heroes and villains against each other, while the latter focuses on a complicated alliance between Iron Man and Doctor Doom, which ends with Doom betraying Stark and imprisoning him with Mephisto—a villain recently introduced to the MCU through the Disney+ series Ironheart.
Kevin Feige, Marvel Studios’ president, has hinted that Avengers: Doomsday is set to be a monumental event. Downey Jr.’s portrayal of Doctor Doom made its official MCU debut during the post-credits scene of The Fantastic Four: First Steps, and is believed to share the same universe as the Fantastic Four. However, the exact reason why the actor’s Doom has Tony Stark’s face remains a mystery, with fans eagerly awaiting answers.
Mixed Reactions to Robert Downey Jr. Potentially Battling Himself
As Doctor Doom is established as the primary antagonist in Avengers: Doomsday and its sequel Avengers: Secret Wars, speculation around Downey Jr. playing both Doom and Iron Man has divided Marvel’s fan base. Many viewers worry that reintroducing Iron Man, even as an alternate version, could diminish the impact of Tony Stark’s heroic sacrifice in Avengers: Endgame. The idea of the actor confronting himself has sparked creative and humorous reactions.
“An iron man vs doctor doom fight would be awesome,”
—User on X/Twitter
“The final fight scene between Robert Downey and Robert Downey would be hilarious.”
—User on X/Twitter
This theory gains traction from Downey Jr.’s recent social media hints, suggesting that the end of the Multiverse Saga may feature several versions of familiar characters clashing, underscoring the complexity of these interconnected storylines.
Star-Studded Cast Set to Return for the Multiverse Epic
Avengers: Doomsday has an extensive cast confirmed to appear from various corners of the Marvel multiverse. Key returning actors include Chris Hemsworth as Thor, Vanessa Kirby as Sue Storm/Invisible Woman, Joseph Quinn as Johnny Storm/Human Torch, and Ebon Moss-Bachrach as Ben Grimm/The Thing. Other familiar faces will include Sebastian Stan, Anthony Mackie, Paul Rudd, Letitia Wright, Wyatt Russell, Tenoch Huerta Mejía, Florence Pugh, Kelsey Grammer, Lewis Pullman, Danny Ramirez, Patrick Stewart, Ian McKellen, Alan Cumming, Rebecca Romijn, James Marsden, Channing Tatum, Pedro Pascal, and Tom Hiddleston, among others.
The sequel, Avengers: Secret Wars, will follow a year later in December 2027, continuing the storyline introduced in Avengers: Doomsday.
Production and Release Plans for Avengers: Doomsday and Secret Wars
Avengers: Doomsday is directed by Anthony and Joe Russo, the duo behind Avengers: Infinity War and Avengers: Endgame, and written by Michael Waldron and Stephen McFeely. The film is scheduled to premiere in the United States on December 18, 2026, as a centerpiece of Marvel’s Phase Six.
As the MCU builds toward one of its most ambitious crossover events, Downey Jr.’s dual portrayal could reshape fans’ understanding of legacy characters and multiverse conflicts. The outcome of these stories will likely have long-term consequences for the franchise’s future projects and character arcs.
