Hafthor Julius Bjornsson can be seen in the new Game of Thrones trailer for season 4 that was recently released. You can see Hafthor topless swinging a sword, and you can find the trailer here below. A film crew of 300 people came to Iceland last summer to film for season 4.
Among filming locations was Thingvellir National Park. A special permit was issued so that the team could film in the park. The Game of Thrones team came to Iceland to film scenes for season 2 and 3, but that was during winter. It will be interesting to see Iceland during summer in season 4.
Hafthor Julius "Thor" Bjornsson was hired to play a role in season 4. Hafthor was born in 1988. He is an Icelandic strongman competitor and actor. He won the Stongest man in Iceland competition three years in a row, and he has won many strongman competitions abroad. He has two times been in third place in the World's Strongest Man competition.