Hafþór Júlíus Björnsson is an Icelandic professional strongman, actor, and former professional basketball player. On 31 January 2015, Björnsson beat a 1000-year-old record set by Orm Storolfsson at the World's Strongest Viking competition in Norway, where he carried a 10 m (33 ft) long 650 kg (1,430 lb) log for five steps Hafþór was cast as Gregor "The Mountain" Clegane for the fourth season of the HBO series 'Game of Thrones (2011)' in August 2013. This was his first main acting role, and 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 with his appearances in season 5. - IMDb Mini Biography By: Pedro Borges

Hafthor Bjornsson competes in the World's Strongest Man competition. He actually began as a basketball player until a knee injury at 20 years old forced him to consider other options. He was Iceland's Strongest Man in 2011 and 2012. He was a top three finalist in the World's Strongest Man in 2012, 2013 and 2014. In 2014 he missed out on winning the competition by only half a point. On February 1, 2015 Björnsson broke a 1,000 year old weightlifting record by carrying a 32-foot (9.7 m), 1,433 lb (650 kg) log for five steps at the annual World's Strongest Viking competition in Norway. The record was set in the late 900s by Orm Storulfsson who carried a similar log for three steps before breaking his back. Despite playing the older brother of Sandor "The Hound" Clegane, he's actually 19 years younger than Rory McCann who plays The Hound. He is the shortest and youngest actor to play Gregor "The Mountain" Clegane on Game of Thrones - Das Lied von Eis und Feuer (2011). The third actor to portray Gregor 'The Mountain' Clegane on Game Of Thrones. He's also the only actor to play him in more than one season.