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Game of Thrones - Cast Interview

On a call with reporters, star Richard Madden said that he "cried the whole way" home on the plane after he shot the final scene from Sunday's devastating episode. In it, his character Robb Stark, Robb's mother Catelyn (Michelle Fairley), his pregnant wife Talisa (Oona Chaplin) and a host of Stark bannermen are betrayed and killed while visiting the seat of House Frey for a wedding.

"It was horrific [to witness] these characters that you've loved get slaughtered," Madden said. "It made me think of my dad when he read all the books. When he got to the Red Wedding ... he put the books down and didn't get back to it for a couple months. He ties Robb Stark in so closely in with me."

Yes, this massacre -- revenge for Robb breaking off a marriage pact with House Frey -- is lovingly known as the Red Wedding by fans of author George R.R. Martin's books, on which Game of Thrones is based. It's the biggest secret that book fans have had to keep since Ned Stark's (Sean Bean) beheading in Season 1. These deaths, however, are even more heartbreaking than Ned's because Catelyn must watch her son die before she gets her own throat cut.

"That's when Catelyn's soul goes flying right out of her," Fairley tells TVGuide.com in a separate interview. "Her grief is so tangible because at this point, she has nothing to live for. As far as she knows, all of her children are dead. She takes the knife up in revenge, which is of course signing her own death warrant by slicing Walder Frey's wife's throat, and therefore inviting her own death."

Fairley marked the end of her time playing Catelyn in her own way. "The wonderful Kevin Alexander, the hair designer, said he'd cut my hair for me afterwards," she says of her last day of shooting. "It's not short, but it's a form of transformation when you end a relationship. But you've still going to have to go through that grieving process."

Check out the rest of the Red Wedding postmortem interviews with Madden and Fairley:

How early in joining this show did you know about the Red Wedding?
Richard Madden: As soon as I got the job, people spoiled it for me. People would be like, "Oh my God, your death, that was so terrible." You're like, "What?"
Michelle Fairley: I knew Catelyn's fate from the word go actually. But it's a wonderful thing [to discuss it] because for so long you can't mention it, but of course that's the one thing that everybody asks you in interviews, but you don't want to spoil it for everyone.

Read more at TV Guide