As an actor, Hafþór is known for playing Gregor "The Mountain" Clegane in the fourth season of the HBO fantasy series Game of Thrones in August 2013. He was the third person to depict the character after Conan Stevens played the role in season 1 and Ian Whyte in season 2. He became the first actor to portray Clegane in more than one season, appearing in the season 5 as well. More: en.wikipedia.org.