Actors' auditions tapes for roles are now all over YouTube, so Kimmel decided to shoot some fake ones with Harington, who plays Jon Snow in the HBO drama.
"This wasn't the only part Kit was in the running for," Kimmel joked to viewers, "he actually auditioned for a couple of other characters on the show which, now that we know him as Jon Snow, is hard to imagine.
"But the producers of Game of Thrones gave us his audition tape - this is the exclusive never before seen Kit Harington screen tests."
Kit is seen 'auditioning' for Cersei Lannister, a character whose name he mispronounces, and shooting for the role of Arya on his knees.
He also offers a less than convincing Hodor and flashes fake breasts as Daenerys Targaryen.
Growing increasingly desperate, his final audition is for the role of Harry Potter.
Kimmel also grilled Harington about spoilers and the rules surrounding them on the show, with the actor revealing that the cast shot fake scenes for season 7 to throw spoiler hunters off the scent.
Game of Thrones season 7 arrives on HBO, Sky Atlantic and NOWTV 16 July.
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