July 31, 2017 11:46 AM EDT

Warning: This post contains spoilers for season seven of Game of Thrones.

Another week, another major plot development on Game of Thrones. And although fans of HBO’s hit fantasy epic know well to expect the unexpected, Sunday’s episode delivered another sad casualty of war.

The episode closed with a bit of a battle switcheroo and an expertly-crafted final exchange between two main characters — Jamie Lannister (Nikolaj Coster-Waldau) and the Queen of Thorns, Lady Olenna Tyrell (Diana Rigg). Fittingly, the cunning, sharp-tongued matriarch was in control until the end — and even as she was dying, she delivered a powerful final blow, revealing to Jamie a killer secret about her prominent role in his son Joffrey’s death: “Tell Cersei. I want her to know it was me.”

It is a fantastic scene of which both players are proud to have been a part, and Rigg says she’s happy you “don’t actually see the final twitches.”

“It’s a beautiful scene, and Nikolaj is wonderful,” Rigg tells PEOPLE of filming her final moments on the show. “When it’s well-written, it’s a joy to do. And you don’t get an awful a lot of always-brilliant writing on television, do you?”

Coster-Waldau agrees. “It’s a great scene,” he says. “I was thrilled [when I read it] because first of all, what happens in the episode, it’s such a great surprise that suddenly they go there and the Lannisters actually were smarter than Tyrion, which was really cool. And then it’s just a great scene. It was truly an honor to be there because she’s given so much to the show with the character, just amazing. And of course both on and off set, she’s wonderful and she’s so smart and so clever and she’s just a brilliant actress. I was very lucky to be there.”

Rigg says there wasn’t any time for mourning on set or for an official farewell after she wrapped her scene, but that she wouldn’t have it any other way.

“No sooner as I die then it was on to the next scene!” she says with a laugh. “It’s pretty pell‑mell on the set. They have a huge schedule and they have to get a move on.”

She adds that what she’ll miss most about playing Lady Tyrell are the well-written “combative” scenes she played with her fellow actors.

“Mostly what you remember and enjoy are the scenes you played with people, you know,” says Rigg. “And quite often they’re combative scenes. The scenes with Charles Dance [Tywin La7nnister] and Lena Headey [Cersei].”

Game of Thrones airs Sundays (9 p.m. ET) on HBO.

This article originally appeared on People.com

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