Short update from GRRM about casting over at his Not A Blog. Here is what he posted:
Poor Doomed Souls Department
Two of three are done, I’m told.
Waiting for signed contracts on the last.
Winter Is Coming: In the comments of my last post, Greg posited that George is referring to the three characters from the prologue here: Gared, Will and Waymar. That makes sense to me. With less than a month to go before filming begins I expect the minor roles will be filling up quickly at this point.