Robert Downey Jr. Will Reprise Role as Doctor Doom in 'Avengers' Sequel

Robert Downey Jr. stunned fans of the Marvel Cinematic Universe when it was announced Saturday that he would play Doctor Doom in a new 'Avengers' film – and the big reveal was done in classic comic book fashion!

The legendary actor showed up as the infamous supervillain in a green costume with a mask over his face at the 2024 San Diego Comic-Con Saturday night. The packed audience had no idea Robert was behind the silver mask as he stood front and center onstage before other hooded figures.

Check out the video ... Robert suddenly ripped off his mask and spread his arms like wings while triumphantly staring into the crowd. The fans went totally nuts, cheering and clapping and shooting cell phone footage of the incredible moment.

Marvel Studios President Kevin Feige had the honor of revealing that Robert will play the role of Doom -- rather than his longstanding 'Iron Man' role -- in the 'Avengers' sequel, "Avengers: Doomsday." Feige also hyped a second upcoming 'Avengers' movie, "Avengers: Secret Wars," and said the Russo Brothers would be directing both flicks.

What a treat for the gazillion 'Avengers' fanatics. But for those of you who might not be up to speed on Doctor Doom, here's a brief rundown of his character.

Doom has long been an enemy of the Fantastic Four – a group of superheroes with superpowers – and the two sides battle one another in Marvel comic books. Doom is known as a scientific genius with a huge ego and a lust for power. He wears a mask to cover up scars that impacted his good looks at one time.