A Knight Of The Seven Kingdoms Cast An Unknown Actor As Ser Duncan For A Good Reason

The "Game of Thrones" universe expanded recently with a new spin-off in the form of "A Knight of the Seven Kingdoms." HBO canceled several "Game of Thrones" spin-offs along the way, but this one went the distance. Most interestingly, the show casts a totally unknown actor in the form of former rugby player Peter Claffey as its co-lead Dunk, aka Ser Duncan the Tall. There's a very good reason for that.

"A Knight of the Seven Kingdoms" takes place roughly a century before the events of "Game of Thrones" and centers on the hedge knight Dunk and his young squire Egg (Dexter Sol Ansell). Just how tall is Ser Duncan the Tall? He's nearly seven feet in height according to George R.R. Martin's source material, which obviously presented a casting challenge. (Claffey himself is six feet, five inches tall.) As showrunner Ira Parker explained in the January 2026 issue of SFX Magazine, that made it essential that series' creatives look outside of established actors. Here's what he had to say about it:

"He was a former professional rugby player who played for Ireland and, obviously, Ser Duncan must be a very large human being. So, when you start there already, it cuts out every single actor in the world who has any experience. So, we knew we were going for an unknown."

"Every single time he came back in, he was exponentially better," Parker added, complimenting Claffey's acting skills despite his lack of experience. "That's sort of what you're looking for when you're going with someone who's just gonna work. And, man, does he just. Not only is he the absolute perfect Ser Duncan for a variety of reasons, and he put himself into that role, but he was also just such a leader for everybody who came in."

"He set the tone on set. He's such a lovely, happy person to be around," Ira Parker concluded.

"A Knight of the Seven Kingdoms" has shorter episodes and is a very different show than "Game of Thrones." That said, its leads are well known to fans, so casting was always going to be hugely important. Given the constraints, it wasn't an easy task, especially because the series' creatives needed to cast an Egg that had chemistry with Peter Claffey's Dunk.

Ultimately, it was Dexter Sol Ansell ("The Moor") who landed the role. But even with Ansell's acting experience, Parker said his casting process was also unique, explaining:

"Dexter was actually the first casting email that I received from our casting director. First batch was a batch of Eggs, and number one, right at the top, Dexter Sol Ansell. I watched it. I said, 'Oh, perfect. He did it. He nailed it.' I called her up and I said, 'What do we do now? Do we sign him up?' They said, 'We have to go through a process here.'"

"We did, and we came all the way back to number one," Parker added. "He's the best child actor that has ever existed on planet Earth. And to see his transformation in season 1 [...] he does some really, some really great stuff for us."

Clearly, it all worked out for the best. In his review of "A Knight of the Seven Kingdoms" season 1 for /Film, Jeremy Mathai called the series "a welcome return to Westeros." The show has already been renewed for season 2 by HBO.

"A Knight of the Seven Kingdoms" is streaming now on HBO Max.