Former HBO veteran actor Ian McShane, star of the HBO series "Deadwood," is returning to the network, as a report from Entertainment Weekly states that he has been cast for "Game of Thrones" season 6. 

As of the moment, his character has not been revealed and the role is said to have only very little screen time, but the report states that he will play a "key role" in next season's plot. 

According to a report from Cinema Blend, there is a very high chance that McShane will be portraying the character Euron Greyjoy, a pirate from the Iron Islands and uncle to Theon Greyjoy (Alfie Allen). This is based on the character description listed on the season 6 casting call that surfaced a few months back.

The description reads: "Pirate, man in his 40's to late 50's. He's an infamous pirate who has terrorized seas all around the world. Cunning, ruthless, with a touch of madness. He's a dangerous-looking man. A very good part this season." 

[Spoiler Warning] In the novels which the series is based on, Euron Greyjoy is introduced as a powerful pirate who cuts off the tongues of his crew to ensure their silence and loyalty. He later becomes King of the Iron Islands after the death of his brother, Balon, and schemes to sail to Mereen and become husband to Daenerys Targaryen. 

If McShane is indeed playing Euron, then this would allow season 6 to conclude the unfinished plotline of the Iron Islands. Balon Greyjoy was last seen in season 3 while Yara Greyjoy's last scene was in season 4. None of them were featured in season 5, save for Theon who was prominently enslaved and kept in Winterfell. 

It is also an interesting tidbit that McShane already played an evil and cunning pirate before when he portrayed Edward Teach aka Blackbeard in "Pirates of the Caribbean: On Stranger Tides."

"Game of Thrones" season 6 premieres in spring 2016.