How is Robert Downey Jr back in the MCU? We break down the potential ways he'll go from Iron Man to Doctor Doom

Marvel Studios' panel at this year's San Diego Comic-Con was pretty subdued for the majority of it's hour-long slot, as it predictably showed a first look at The Fantastic Four and a trailer for Thunderbolts* , and revealed who Giancarlo Esposito is playing in Captain America: Brave New World.

That was, until Kevin Feige and newly-appointed Avengers 5 directors Anthony and Joe Russo dropped the bombshell of all bombshells: Robert Downey Jr. will be the MCU's Doctor Doom.

The reveal was met with applause and excited shrieks, but the reception outside of Hall H has been a little more mixed, it seems fair to say. While some are intrigued by the prospect of Earth's Mightiest Heroes having to face off against a villain who shares a face with their former ally, others have dubbed the casting "lazy" and "uninspired". Others, meanwhile, are just straight-up confused.

Well, we're here to cater to the latter group, as we try and break down how the Iron Man actor can feasibly return as an entire different character, as well as who Doctor Doom is. Of course, Avengers: Doomsday is still a long way away yet, and anything can happen between now and then – hey, who's to say Marvel doesn't already have a few tricks planned. For now, though, we'll work with what we've got...

So, who is Doctor Doom?

Created by Stan Lee and Jack Kirby, scientist and politician Victor von Doom first appeared in The Fantastic Four #5 way back in July 1962. Helming from the fictional Eastern European region of Latveria, he was left horrifically scarred after he moved to the US to study, invented a machine that could supposedly communicate with the dead, and attempted to talk to his late mother, who was killed by Mephisto and whom he inherited the potential to wield magic from.

Following his expulsion from State University in Hegeman, New York, he travelled the world, eventually stopping in Tibet, where he forged himself a metal mask and suit and learned how to master the mystic arts. Eventually, he became so powerful that his wizardry was considered secondary only to the Sorcerer Supreme.

His most common enemies in the comics include Spider-Man, Iron Man, Doctor Strange, Black Panther, the X-Men, the Avengers and, of course, Marvel's First Family.

How can Robert Downey Jr be Doctor Doom?

The most likely justification for Doctor Doom having the exact same face as Tony Stark is that he's a variant; a separate character who looks like Iron Man, but has lived an entire different existence than him on another timeline. Perhaps even on another Earth? Think Sylvie in Loki, the Disney Plus show that ushered the concept of 'variants' into the MCU.

Variants can, well... vary when it comes to how similar they are to their multiversal counterparts. Sylvie is a Loki variant, but has her own unique personality and, of course, looks entirely different from Tom Hiddleston's God of Mischief. The Loki in the same show, though, is technically a variant, too, and is basically the exact same person as the Loki who was introduced in Thor (2011). In Doctor Strange in the Multiverse of Madness, Benedict Cumberbatch's titular hero encounters a few different versions of "himself", though we don't spend enough time with them to find out how alike they all were. That said, we can assume Sinister Strange and Stephen Strange are poles apart...

Downey's Doom looks set to be a new type of variant altogether; like Sylvie, in the sense that he'll be his own character, but like Loki and Strange, in that he'll look just like Stark. That is, if he we actually see his face onscreen...

In the comics, Doom is almost never seen without his mask, which could suggest that the Oppenheimer star's iteration will do the same. We'd argue, though, that Marvel wouldn't have made such a big deal about the character being played by Downey if it just had plans to cover him up for both Avengers 5 and Avengers 6.

Finally, the character could be entirely CGI and Downey just does the motion-capture work and voice for him, like Josh Brolin did with Thanos, While it's possible, that doesn't really seem necessary, however, given that Doom is human-looking, rather than a ginormous purple alien.

"Maybe it's a Doombot," Reddit user Bonedraco1980 claimed , while another added: "That would be interesting. A fake Doom designed to f*** with the heads of the heroes by impersonating one of their former leaders while the real Doom waits in the wings." (In the comics, 'Doombots' are robotic replicas of Doom in his armored form).

After Downey's casting was announced at SDCC, Marvel Comics writer Deniz Camp took to Twitter to say : "If you want to understand Robert Downey Jr. as Doom, you MUST read Ultimates 4 on Sept 4th. (or whenever it comes out)." In that series, Doom is actually Fantastic Four's Reed Richards and is considered a hero, which is especially interesting when you notice how, on stage, Joe Russo explicitly namedropped "Victor Von Doom".

Other actors that have played dual Marvel roles

Despite the controversy it's stoking, Robert Downey Jr won't be the first actor to play more than one Marvel character on screen.

* Warning! This section contains major spoilers for Deadpool and Wolverine. If you've yet to see the movie and don't want to know anything that happens, turn back now!*

Josh Brolin brought Avengers villain Thanos to life across multiple movies, playing antagonist Cable in Fox's Deadpool 2 in between. Gemma Chan played Minn-Erva in Captain Marvel, before portraying Sersi in Eternals. Linda Cardellini is Hawkeye's wife Laura Barton, but also voiced Lylla, the ill-fated otter in Guardians of the Galaxy Vol. 3.

Mahershala Ali, who's geared up to Blade, was Cottonmouth in Netflix's Luke Cage and Defenders, while Michael B. Jordan has played both Johnny Storm/Human Torch and Black Panther's Erik Killmonger – and there's a few more where those came from, too!

Most notably, perhaps, though, and one that is most on-par with Downey's double-dipping is Captain America himself, Chris Evans, famously playing Johnny Storm/Human Torch in Tim Story's Fantastic Four (and he reprised the role in Deadpool and Wolverine , just recently).

Avengers: Doomsday is due to be released in May 2026. For more, check out all the upcoming Marvel movies and shows on the way, as well as our guide to how to watch the Marvel movies in order .