Additionally, Jacob Anderson has been cast as Grey Worm, the leader of the group of slave soldiers Unsullied.
Plucked from across the pond, both British actors are newcomers who will certainly make an impression with their roles on the HBO series.
In other casting news...
Rob Huebel has landed a guest role on "Up All Night." The "Children's Hospital" actor will appear on the NBC comedy as Chris' (Will Arnett) irritating college roommate. [TV Guide]
"ER" alum Goran Visnjic will co-star on "The Red Widow." Visnjic is set to play Schiller, the mafia mob boss on the ABC drama. [Deadline]
Rob Corddry is taking on "Ben & Kate." The "Children's Hospital" star will appear as a character named Buddy who hangs out in the bar where BJ (Lucy Punch) and Kate (Dakota Johnson) work. [EW]
J.K. Simmons is headed back to work. Simmons will return to "Men At Work" as the not-so-friendly publisher of Full Steam magazine, with his character butting heads with Lindsey, played by John Michael Higgins. [TV Guide]