HBO provides some casting confirmations 

We’ve had quite a few castings leak out via Twitter o through the actor’s CVs on Spotlight o their agency profile. Although these were strong signs that the casting was legit, it is still nice to get official confirmation from HBO.
parole chiavi: Game of Thrones, season 2, casting, steven cole, kovarro, nicholas blane, spice king, tony way, dontos hollard, sam callis