Emilia Clarke formed a bond with the HBO show's latest casualty on the first day of filming nearly 10 years ago


As most Game of Thrones fans know by now, last night’s episode, “The Long Night,” was a doozy.

Star Emilia Clarke posted a tribute on Instagram Monday to one of the episode’s major casualties, celebrating her love for her fallen costar Iain Glen’s character Ser Jorah Mormont, who was killed while defending Clarke’s Daenerys in the epic Battle of Winterfell.

Clarke, 32, recently told PEOPLE that she developed an almost instant friendship with and appreciation for Glen after he helped comfort her during a mishap on her very first day of filming Thrones nearly 10 years ago.

“The first day on set I fell off my horse and cried,” she recalled. “I have the most visceral memory of the first day, it is Iain Glen calming the horse, calming me, and I was like: ‘That is my friend for life.’ ”

The actress called Glen “simply the best” in her Instagram post, which included a smiley pre-tragedy photo of herself with Glen on the Thrones set.

Glen, 57, told PEOPLE that his last day on set as Ser Jorah “was very emotional,” and that he tried to give a farewell speech to the cast and crew but “I was a bit too tearful,” he admitted. “The words didn’t come out.”

Emilia Clarke as Daenerys Targaryen and Iain Glen as Jorah Mormont
Emilia Clarke and Iain Glen in “The Long Night,” the third episode of Game of Thrones Season 8
| Credit: Helen Sloan/HBO

The actor, who is well-known for his work in countless other films and TV shows like 2001’s Tomb Raider and the Underworld franchise, said his recognition factor is “higher than it’s ever been,” and that he is most grateful for the journey of being on eight seasons of Thrones.

“I’ve really enjoyed the journey as a whole,” he said. “I loved going on the journey with Peter Dinklage, we had great fun doing that. But Daenerys and being by her side has always been my strongest association.”

Asked whether the cast will be keeping in touch, no matter who lives and dies on the show, Clarke assured PEOPLE that they all frequently communicate.

“We do have a WhatsApp group chat, so yeah we are [in touch],” she said with a laugh.

The final season of Game of Thrones airs Sundays on HBO.