How Is Robert Downey Jr. Playing Doctor Doom in Avengers: Doomsday?

Avengers 5 has a new subtitle, Doomsday, and a new villain, Robert Downey Jr.’s Doctor Doom. Wait a minute: How is Robert Downey Jr. – the guy already immortalized as Tony Stark/Iron Man – playing Doctor Doom in Avengers: Doomsday?

Related: Avengers: Doomsday: Does Iron Man Become Doctor Doom in Marvel Comics?

Robert Downey Jr. Playing Doctor Doom in Avengers 5, Explained

Right now, nobody outside Marvel Studios’ inner circle knows exactly how Robert Downey Jr. portraying Doctor Doom in Avengers: Doomsday is going to work. That said, the obvious explanation is that directors Joe and Anthony Russo will use the MCU’s multiverse conceit to justify their Avengers 5 casting coup.

After all, previous and upcoming MCU installments have already confirmed that not all heroes and villains look the same in each universe. For example, John Krasinski portrays Reed Richards/Mister Fantastic during Doctor Strange and the Multiverse of Madness‘ Earth-838 sequence, whereas Pedro Pascal will fill the role in 2025’s The Fantastic Four: First Steps. So, it wouldn’t be a huge leap of logic if the Tony Stark of Earth-616 and a Doctor Doom from elsewhere in the multiverse both end up sharing Downey’s likeness.

Related: Is Robert Downey Jr.’s Doctor Doom in The Fantastic Four: First Steps?

Of course, the Russo Brothers could have something else planned, instead. Avengers: Doomsday‘s Doctor Doom could even be an evil variant of Tony. They’re both armor experts, after all! That seems unlikely, though. At San Diego Comic-Con 2024, the Russos explicitly referred to Doomsday‘s antagonist as Victor von Doom, seemingly ruling out a “evil Tony” twist.

Heck, Avengers: Doomsday may not acknowledge the RDJ casting overlap at all. In the comics, Doom rarely removes his mask, so there’s a chance Downey’s face won’t even appear on screen! We’ll just have to wait until closer to Doomsday‘s 2026 release for answers.

Does Iron Man Become Doctor Doom in the Comics?

Yes – kinda. It’s not really as simple as the Tony Stark Iron Man from mainstream Marvel canon becoming Doctor Doom, because that doesn’t happen. What does happen is that the Tony of Earth-11029 switches bodies with that reality’s Victor von Doom, and eventually assumes the Doctor Doom mantle. He never becomes a baddie, though.

Related: All Major Actors & Cast List for The Fantastic Four: First Steps

In a fun reversal, Doctor Doom has become Iron Man before, too. In the 2016 12-issue Infamous Iron Man series, Victor von Doom subs in for Tony while he’s MIA following the Civil War II crossover. Again, this isn’t quite the same as Iron Man transforming into Doctor Doom, and it seems unlikely the Russos will reference Infamous Iron Man in Avengers: Doomsday.

Avengers: Doomsday is slated for release in May 2026.