Robert Downey Jr. Fully Committed to Doctor Doom, Crafting Backstory and Costume Ideas

Marvel fans, get ready for a game-changing return! Robert Downey Jr. is stepping back into the Marvel Cinematic Universe, but this time, he’s trading in his Iron Man suit for the mask of an infamous villain—Doctor Doom. After a decade of playing the beloved Tony Stark, Downey is taking on a darker role, and according to Joe and Anthony Russo, he’s going all in.

In an interview with Entertainment Tonight, the Russo brothers revealed just how much work is going into bringing Doom to life. “It has been a very intense process developing the character,” they said, emphasizing the depth Downey is bringing to the role. With Avengers: Doomsday set to hit theaters in May 2026, production is gearing up to start soon.

“He is so immersed in it. He is so dialed in,” Joe Russo shared, praising Downey’s dedication. “He’s writing backstory, costume ideas… We were just on the phone with him this morning before we got here talking about it. He just loves really rich three-dimensional characters. He sees a real opportunity here with the character.”

Fans were left stunned when Downey and Marvel Studios announced his casting as Doom at last year’s Comic-Con. The Oscar-winning actor played a key role in launching the MCU with Iron Man in 2008 and appeared in 10 Marvel films over 11 years, including two Iron Man sequels and four Avengers movies. His character’s emotional farewell in Avengers: Endgame made his return as a villain even more shocking.

Doctor Doom is set to be at the heart of Avengers: Doomsday, a film that also marks the Russo Brothers’ long-awaited return to Marvel after their record-smashing Avengers: Endgame in 2019. The duo will also direct its 2027 follow-up, Avengers: Secret Wars.

Downey’s shocking comeback even caught his former Marvel co-stars off guard. Jeremy Renner, who plays Hawkeye, told US Weekly that Downey never gave the original Avengers a heads-up about his return.

“The son of a b---- didn’t say anything to me,” Renner joked. “We’re good friends. There’s the Avengers family chat. The original six. He said not a peep. I got online and started blowing up his phone like, ‘What’s going on? You’ve been hiding this from us the whole time?’ It’s exciting news. I’m really, really excited about it.”

When Jonathan Majors got arrested in March 2023, it threw everything into complete chaos for MCU fans. Many weren’t sure if he’d come back as Kang. In Loki Season 2, it looked like they were wrapping up his story and moving on from the time-bending villain. If that wasn’t enough, Majors was reportedly fired after being found guilty of reckless assault and harassment in a big, public trial.

The exciting news about Downey Jr. came out at Marvel Studios’ panel at San Diego Comic-Con. His return shows that Marvel is still all in on the Multiverse Saga, just with a new direction and without Kang.

TMZ caught up with Majors, and he said he was “heartbroken” about the news, showing his love for Kang and his other characters. He also talked about Downey Jr. and “The Flash” star Ezra Miller getting second chances after their own legal issues. Downey Jr.’s past troubles with addiction led to several arrests, but he’s now a huge star and just won an Oscar.

“I think it’s fair that Mr. Downey has been greeted with patience and curiosity and love. Mr. Miller’s gotten the same treatment and they’re being allowed to work at their art and be creative at that level,” Majors said. “I didn’t really get that.

Marvel fans won’t have to wait too long to see Downey’s Doctor Doom in action. Avengers: Doomsday is set to hit theaters on May 1, 2026, from Disney and Marvel Studios. Let the countdown begin!