As the ol' Westeros saying goes: "The Iron Bank will have its due," and it looks like Mark Gatiss will be back make sure it bloomin' well does. 

Sherlock co-creator, writer, producer and actor will apparently reprise his role as Tycho Nestoris, the fantasy world's most fearsome banking executive, in season 5 of HBO’s fantasy hit Game of Thrones.

Nestoris made his debut in season 4 as a representative of the Iron Bank of Braavos: the bank that most of Westeros' kings borrow their gold from. He was seen granting a loan to Stannis Baratheon after it was established that the Lannisters were deep in the Iron Bank's debt. 

According to Entertainment Weekly, Gatiss is expected back on the set of the show in Croatia next week.

His return means that season 4's appearance wasn't merely a cameo, and that Gatiss could play a larger role in the future of the show. 

Game of Thrones season 5 is expected to air on Sky Atlantic next year.