Robert Downey Jr. returns to the MCU with other confirmed actors including stars Chris Hemsworth and Tom Hiddleston, 'X-Men' stars like Patrick Stewart and Ian McKellen, and a good chunk from the studio's 'Thunderbolts.

"Avengers: Doomsday" finds brothers Joe and Anthony Russo back in the directors chairs. They return to Marvel having helmed the Captain America films "Captain America: The Winter Soldier" and "Captain America: Civil War," as well as "Avengers: Infinity War" and "Avengers: Endgame."

Rebecca Romijn, 52, will officially return as Mystique. She starred as the shapeshifter in “X-Men, X2: X-Men United,” “X-Men: The Last Stand” and “X-Men: First Class and Joan in The Punisher.”