Early fan favorite to play Ramsay, Iwan Rheon has been cast in Game of thrones.
Iwan Rheon is an Olivier Award-winning Welsh stage and television actor and singer, and a graduate of the London Academy of Music and Dramatic Art.
His agency CV says he will play the role of "Boy", which does make some sense considering how the character is introduced. Although I hope his rhyming moniker makes its way into the series as well!
No offical word from HBO on the casting or the specific role, but he was spotted with cast members at a Belfast pub. Personally I think if his CV says he is cast - he is cast.