Legendary acting veteran Max von Sydow is joining the cast of HBO's big budget fantasy series "Game of Thrones" reports EW. Von Sydow is set to play the Three-Eyed Raven, the mystical tutor of Bran Stark. He'll take over from another actor who was briefly seen in the season four finale in the role. Von Sydow will feature in the show's sixth season which is currently in production ahead of airing in April next year. Like the recently cast Ian McShane, von Sydow is not expected to have a lot of screen time but is in a role that is crucial.