It seems that Game of Thrones has troubles keeping actors to play Gregor Clegane, the Mountain, also known as the Hound’s older, meaner, brother. You may remember him for this:
Oddly enough, they had to get another guy to play him for the next season. And then that guy had some problems and now they have a third guy: Hafþór Júlíus Björnsson. He is apparently one of the last giants in Iceland. The dude is 6’9 and well, just look at him.
And here is a picture of him from the set of the upcoming season: