Harington was not the only cast member moved by the end of the series. In EW's piece, Sophie Turner describes reading the scripts as "completely overwhelming” and says it left her feeling "numb." Similarly, Lena Headey, who plays the sinister Cersei Lannister, described the experience of filming the final season as leaving her with "a great sense of grief."
What exactly could make all of them so stressed out? Again, the article is light on spoilers, but it does note that there was a 55-day night shoot for a (presumably) climatic battle. (For some context, Season 6's "Battle of the Bastards" required a 25-day shoot.) "It’s brutal," says Peter Dinklage in the article. "It makes the Battle of the Bastards look like a theme park."
Then again, as exciting and grueling as the epic action sequences on Game of Thrones can be, the most moving parts of the show tend to be smaller character moments. In the piece, EW writer James Hibberd, who visited the set in Belfast, describes arriving on set and being "stunned" and "freaked out." Specifically, he notes, "There are characters in the finale that I did not expect."
Could Sean Bean be back as some sort of exposition-delivering ghost figure? Is this the Lady Stoneheart reveal some fans have clamored for? Did Grey Wind return from wolf heaven? We're going to have to wait until 2019 to find out exactly how it shakes out. If Kit Harington's tears are any indication, start investing in new boxes of tissues now.