Thanks to ezeqiel09, in fact this is a Harrenhal scene. And the “Lannister guard” is, in fact, Ser Gregor Clegane—it’s a Clegane cloak mixed with a Lannister red cloak that he’s wearing here, not Joffrey’s stag-and-lion. The role was recast as Conan Stevens has gone on to film in The Hobbit and Spartacus: Blood and Sand, and is now played by Ian Whyte.
Copyright ©HBO