The 31-year-old actor, who became an overnight sensation courtesy the hit HBO series where he portrays Jon Snow, said initially he refused to read the script for the final season which was sent to all the show's stars in advance.
"I walked in saying, 'Don't tell me, I don't want to know'," Harington told Entertainment Weekly.
"What's the point of reading it to myself in my own head when I can listen to people do it and find out with my friends?" he added.
Harington cited another instance when he became emotional and said it was during the table read for the last episode.
"The second time was the very end. Every season, you read at the end of the last script 'End of Season one,' or 'End of Season two,' This read 'End of 'Game of Thrones'.' And you realize, okay, it's really happening," the actor said.
The eighth and final season of the show will air next year.
(With inputs from agencies.)