"We were excited about the prospect of the character, because she's mentioned in passing in the previous season," co-showrunner D.B. Weiss tells us in the after-episode commentary. "The more we thought about it, Jon is gonna come up against so many old guys with beards in the North, that, like, what if she was a tougher audience?"
Tough doesn't even begin to describe Ramsey's performance. Weiss added, "It also was terrifying because it's putting a lot of dramatic weight on the shoulders of somebody who needs to be very young, and we're very lucky to have found Bella because she is doing such a great job of just talking smack to these guys who are used to being the heroes who make proclamations."
And he wasn't the only one blown away: as co-executive producer Bryan Cogman said in an interview with Entertainment Weekly, "Bella is a terrific young actress -- the whole cast and crew were very impressed. I think, much like the character does with Jon, Sansa, and Davos, Bella kept Kit, Sophie, and Liam on their toes!"