Cunningham will play Davos Seaworth, a family man with a checkered past whom fellow Season 2 newcomer Stannis Baratheon will enlist to help steal the series' central throne from King Joffrey (Jack Gleeson). (At least, he'll do that if the series closely follows its source material, George R.R. Martin's Clash of Kings.)
Cunningham's signing is the latest in a spate of Thrones casting news. On Monday, we reported that Stephen Dillane will play Stannis, and Carice van Houten will portray Melisandre. Earlier, we learned that Gwendoline Christie has been cast as Brienne, while another premium cable alum, Natlie Dormer (The Tudors), will take on the role of Margaery Tyrell.
Entertainment Weekly assures us that Davos is the last "major role" that needed to be filled for the show's second season.
Game of Thrones is scheduled to return to HBO in 2012.