Mark Gatiss recently signed on to play a role in Game of Thrones, but everyone involved kept their lips sealed regarding specifics. Despite their best efforts to keep it a secret, the word is out. Winter is Coming checked out the actor’s résumé, and it’s right there. He’ll be playing Tycho Nestoris. The character is a representative of the Iron Bank of Braavos; the bank has lent a lot of money to the Crown and they take debt very seriously.
The news is surprising because Nestoris doesn’t show up until quite a bit later in the books. This could mean they’re combining him with another character. Regardless of the timing, I think Gatiss is a fantastic choice for the role.