Outside of the MCU, Downey has fronted Guy Ritchie’s excellent ‘Sherlock Holmes’ series, given a stellar performance opposite Robert Duvall in The Judge, and, of course, captured a ‘Best Supporting Actor’ Oscar for his role as Lewis Strauss in Christopher Nolan’s Oppenheimer.

Julian McMahon, who played Doctor Doom in the two 2000s Fantastic Four movies, also believes Downey Jr. will prove a perfect fit for the villainous part. "If you've got Robert Dow

With Robert Downey Jr. set to play Doctor Doom in the MCU, there's one key character flaw that I'm most excited to see him bring to the big screen.