Hafþór Júlíus Björnsson is an Icelandic professional strongman, actor, and former professional basketball player.
He plays Ser Gregor "The Mountain" Clegane in the HBO series Game of Thrones.
Set 17 years before the events of Game of Thrones, Robert's Rebellion depicts Robert Baratheon's war to unseat the Mad King, Aerys Targaryen, as King of the Andals and the First Men.
