Alex Graves tells THR he did a double take when learning he would be overseeing Sunday's disturbing incest moment: "You read the scene and go, 'Wait, who's directing this?' "

[WARNING: Spoilers ahead for Sunday's episode of Game of Thrones, "Breaker of Chains"]

Game of Thrones director Alex Graves shocked fans last week with Joffrey's (Jack Gleeson) death. This week he tackled the aftermath of the Purple Wedding in an episode that contains one of the series' most disturbing scenes to date.

As Cersei (Lena Headey) is mourning her son, Jaime (Nikolaj Coster-Waldau) comes in to comfort her and pay his respects. Things get hot and heavy between the siblings/lovers, but when Cersei attempts to put a stop to it, Jaime rapes her. To add another layer to the already disturbing scene, their son's dead body is just inches away. (Read a full recap here.)

"The whole thing for me was about dead Joffrey lying there, watching the whole thing," Graves tells The Hollywood Reporter. "I wanted to make sure I had Jack in there as much as I could. Of course Lena and Nikolaj laughed every time I would say, 'You grab her by the hair, and Jack is right there,' or 'You come around this way and Jack is right there.' "

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Why was it key that Joffrey was in the scene?

"He is their first born. He is their sin. He is their lust, and their love -- their everything," says Graves. "If he's gone, what's going to happen?"

Here, the director breaks down the rest of the episode, revealing which scene he thinks has "one of the best speeches in the series" and why its events are essential for the rest of the season.

This feels like Tywin's episode. What was filming his scene with him and Tommen like?

That was one of the greatest days I've ever had filming. To film Charles (Dance) kidnapping Lena's son with words for three minutes of monologue -- and to have Lena keeping up with him at the highest bar of acting possible with no words at all -- was a joy. It was directorial crack to do that scene. It was one of my favorite scenes I've ever shot. It's almost like a build from Ordinary People meets a Hitchcock movie, because you're sitting here going, "This is so dysfunctional and bizarre." She's a wreck. Tywin is really going on about this historical stuff, and you slowly start to go, "He's kidnapping her only boy," because she's not going to have him anymore. And then he succeeds, and then Jaime comes in and he rapes her. That was like -- you read the scene and go, "Wait, who's directing this?"

That whole scene has to be one of the most taboo, disturbing things that has happened on the show.

I'm never that excited about going to film forced sex. But the whole thing for me was about dead Joffrey lying there, watching the whole thing. (Showrunners) David (Benioff) and Dan (Weiss) loved that, and I was like, I wanted to make sure I had Jack in there as much as I could. Of course Lena and Nickolaj laughed every time I would say, "You grab her by the hair, and Jack is right there," or "You come around this way and Jack is right there."

Why was it so important to have Joffrey's body in the scene?

He is their first born. He is their sin. He is their lust, and their love -- their everything. If he's gone, what's going to happen? Jaime is still trying to believe as hard as he possibly can that he's in love with Cersei. He can't admit that he is traumatized by his family and he's been forced his whole life to be something he doesn't want to be. What he is -- but has to deny -- is he is actually the good knight, like Brienne.

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The Daenerys stuff was pretty crazy too. It calls back to the scene with the Unsullied you directed last year.

That was when I was done prepping the Purple Wedding. I went home, and instead of sleeping I had to plan that. I always called Meereen my 8 p.m. to 2 a.m. part-time job. If you get into the marrow of that daily storyline it is always, always Emilia (Clarke). She is the most motivating, stimulating young actor of many I've worked with. She is utterly old-school professional. She carries around a ripped up, wrecked, ruined version of the book we're shooting, because she is one of the only people who reads the books. And behind all of that, every time you say action, you watch this performance occur that is Nirvana.

What was she like shooting the episode's big Daenerys finale?

You're in a rock quarry with like 500 smelly guys, and the crew is exhausted, and everybody is on edge, and Emilia comes on set and all of a sudden the whole crew is like (in a sing-songy voice): "Emilia! Good morning, Emilia. How are you?" It brings out the best in everybody. It's like Audrey Hepburn has just walked onto the set. And nobody is more gracious than she is on the set. It's just great. She is a good example.

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Earlier on, we had this very sad scene. There's a cute family, where the father and son are talking, and then the dad is immediately shot with an arrow. What was the purpose of that?

What it's saying is no one's safe who's up in the North. It's saying that you're not out of harm's way no matter how remote your village is, because the two warring forces there are now unavoidable and are headed for something big. What we're watching play out is the Wildling's strategy, which is they are doing such horrible things that Jon Snow will have to come down and fight them. And Jon has to resist them as long as they can.

Arya and the Hound also meet an adorable family, whom the Hound robs but justifies his robbery with a great speech.

That's one of the best speeches in the series, and it's the times they live in. The Hound is saying, "Arya. You're a lot like your father. Don't be too much like your father or you're going to end up dead." And that's a very important turning point for her. It's really a question of who is she going to become? This girl who has seen her family murdered over and over again? What's going to happen to this traumatized kid, and how is she taking it in?

You also directed episodes eight and 10 of this season. What can you tell us about what's next for Thrones?

Episode three is in part an aftermath episode, where you settle and everything takes a turn toward the second half of the season, whether it's Castle Black, where the battle is coming and they realize they are going to have to do something. Episode three is actually a series of really beautifully written scenes that smartly ends with Meereen, which is the beginning. You have all these beautiful scenes to play out, and then you get a big smashing end to the episode, which is like the opening sequence of a movie as the end. Three is really setting up the last three episodes of the season.

Email: Aaron.Couch@THR.com

Twitter: @AaronCouch