The actor who played Hodor on Game of Thrones is also a professional what?

This is how bad the wait for Winds of Winter has gotten — all of the actors associated with GoT projects have started taking up other professions.

Alright, that joke doesn't really make sense, but I do always love finding out about the secret lives of actors — and I'm not just talking about how everyone seems to play bass in a blues band, but alternate jobs that are actually surprising.

The actor that played Hodor is one such person — what's his other job?