Game of Thrones' The Mountain drops 100 pounds in preparation for his boxing debut

Hafthor Bjornsson, who played The Mountain in 'Game of Thrones', has reportedly dropped more than 100 pounds in preparation for his boxing debut.

The Icelandic actor and strongman will reportedly take on his British rival in September, with the fight already billed as ‘the heaviest in history’. He took Irish boxer Steven Ward in an exhibition bout in Dubai on January 15.

The 32-year-old actor, who is also one of the most successful strongman competitors, shared his dramatic weight loss with a picture on Instagram alongside a caption that included: "From 205kg to 155kg."

He retired from competition in November after winning Iceland's Strongest Man for the 10th consecutive year. He won World's Strongest Man in 2018.

Bjornsson recently shared part of his new fitness regime on his YouTube channel. In the video, he broke down his strict diet, which includes four meals and starts with three eggs and 200 grams of chicken, as well as a smoothie made with 150 grams of yogurt, 100 grams of berries, and 40 grams of oats at breakfast before hitting the gym, where he works on boxing technique with his trainer.

"I'm extremely happy with my shape right now," The Mountain said during the video. "When I started this journey, I weighed 205 kilograms. And now I'm down to 155. Feeling good, feeling healthy."