Jon Favreau has confirmed that Robert Downey Jr. almost played a totally different Marvel role. The actor debuted as Iron Man in 2008, and played the hero all the way up to 2019's Avengers: Endgame.
In the book Marvel Studios: The Making of the Marvel Cinematic Universe by Tara Bennett and Paul Terry, released in 2021, Favreau mentioned that Downey had a meeting with Marvel about the possibility of playing Doctor Doom (H/T CBR.com).
In a Marvel interview to mark 15 years of Iron Man, Favreau and Feige recalled the story. "I remember that Robert had come in for a general [audition] on it, and I remember you had all met with him already for Doctor Doom or something on another project. I think he had come through on maybe Fantastic Four," commented Favreau, with Feige adding: "Right, right."
Doctor Doom is typically a Fantastic Four villain who wears a distinctive metal mask. He has yet to be introduced in the MCU, though he's been played before in Fox's Fantastic Four movies by Julian McMahon and Toby Kebbell.
It's difficult to imagine Downey Jr. as anyone but Tony Stark, though we can't deny that we're intrigued as to how he would have played as chilling a villain as Doctor Doom.
Before the Fantastic Four movie arrives to kick off Marvel Phase 6, we've got the likes of The Marvels, Captain America: New World Order, and Disney Plus show Secret Invasion still to come from Marvel Phase 5. In fact, the fifth Phase of the MCU has only just begun with the release of Ant-Man and the Wasp: Quantumania and Guardians of the Galaxy 3.
Secret Invasion is next up on the Marvel release slate, arriving June 21, 2023. Until then, check out our guide to all the upcoming Marvel movies and TV shows to get up to speed with everything else on the way.