Robert Downey Jr. Had ‘Already Met’ to Play Doctor Doom in 2005’s ‘Fantastic Four’ Before Being Cast as Iron Man, Director Jon Favreau Once Said VarietyWhy Robert Downey Jr.’s Return to Marvel Could Work—Or Not TIMEAvengers: Secret Wars Finally Has the Villain It Needs in Robert Downey, Jr.’s Doctor Doom IGNRobert Downey Jr. As The MCU’s Doctor Doom? There’s Two Explanations ForbesRobert Downey Jr. returning to MCU as Doctor Doom in ‘Avengers: Doomsday’ Entertainment Weekly News