The British actor shot to fame playing Jon Snow in the hugely successful HBO series, which ended in May, and now he'll be teaming up with former co-star Richard Madden in the superhero blockbuster, which will also feature Angelina Jolie and Salma Hayek.
The casting news was revealed at Disney's D23 Expo in Anaheim, California on Saturday, August 24.
Marvel boss Kevin Feige revealed Harington will play Dane Whitman in the film, which is scheduled for release in November, 2020.
Madden will portray Ikaris, Hayek has been cast as spiritual leader Ajak, and Jolie will tackle warrior Thena.
Director Chloe Zhao has already started work on the film adaptation of the Jack Kirby comic in London. Feige is producing.
Disney's biennial D23 Expo continues on Sunday at the Anaheim Convention Center.
The "Black Panther" sequel was also making headlines at the event on Saturday, with director Ryan Coogler and Feige revealing the film will hit cinemas on May 6, 2022, and there were also major previews and teasers for "Black Widow", animated Pixar musical "Soul", "Cruella", "Mulan", and the next "Star Wars" movie, "Star Wars: The Rise of Skywalker". Meanwhile, newlywed Dwayne 'The Rock' Johnson and co-star Emily Blunt wowed fans when they appeared and introduced clips from their new comedy "Jungle Cruise", which will open in July, 2020.
There was also a big reaction when Walt Disney Studios Motion Picture Production president Sean Bailey brought out Angelina Jolie as part of a "Maleficent: Mistress of Evil" segment.
"I missed her and I love playing her," the actress told fans. "In the first film we brought two people, two creatures, who were very different and historic enemies in many ways, but they are family and we brought them together."
But the best was left until last as Evan Rachel Wood and Sterling K. Brown took to the stage to introduce the "Frozen 2" part of the event, with actress Wood revealing she will be playing Elsa and Anna's mother in the film. After a brief preview, the much-anticipated sequel's stars, Idina Menzel, Josh Gad, Jonathan Groff, and Kristen Bell, hit the stage to perform new song "Some Things Never Change" as confetti rained down on them.