Grant has many credits to his name, including the classic indie film Withnail & I. His more recent work includes appearances on Doctor Who, Downton Abbey, and Girls.
While HBO has declined to release any details about Grant’s character, that hasn’t stopped fans from speculating. Many have him pegged as Randyll Tarly, father of Samwell Tarly and the recently cast Dickon Tarly and a military mastermind. Others believe he’s been cast for the surprise appearance of Howland Reed, Ned Stark’s old friend and the last survivor of the Tower of Joy.
Game of Thrones will return for Season 6 on HBO in 2016.