While there are still no details about the role of the 72-year-old British actor, speculations are rife that he will likely be taking on the role of Randyll Tarly, the father of Samwell Tarly.
Sam, played by John Bradley, is a brother of the Night Watch and is a close friend of the Jon Snow. In Season 5, Stannis Baratheon, played by Stephen Dillane, was talking to Sam when he learned of his surname as Tarly. He told Sam that his father was one of the greatest soldiers in Westeros and the only man who ever defeated Robert Baratheon.
In Season 1, Sam said that he was forced to go to the Night Watch by his father, but he did not mention anything about him. Gilly eventually noticed that Sam was highborn and not lowborn just like most of them and many brothers in the Night Watch.
In the books of George R.R. Martin for the fantasy novel series “A Song of Ice and Fire,” Randyll is supportive of House Tyrell.
If fans can recall in Season 5, House Tyrell could certainly use a warrior like Randyll because Margaery, played by Natalie Dormer, and her brother Loras, played by Finn Jones, are imprisoned by the High Sparrow, played by Jonathan Pryce.