Mixed martial artist Gunnar Nelson was injured in a friendly matchup with Games of Thrones star Hafþór Björnsson, who fans will remember as Gregor "The Mountain" Clegane in the HBO fantasy drama.

After tapping Björnsson with an armbar in Round 1, Gunnar tried to repeat the move, only to have the much heavier Björnsson fall on top of him -- twice. "Something in me was like: 'I’m not going to say anything now,'" Nelson -- who heard a pop in his ribs during the May matchup, told MMA Hour. "I’m just thinking: 'I have to wait for him to show his neck, and we can get this over with. Because it’s too late to stop now and say I hurt myself.'"

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"It’s hard to stop when you’re in it," Nelson continued. "Like, not that we were going crazy, but it’s just, you know… It was not his fault or anything. It just happened. He wasn’t going spastic or anything. He’s just 160 kilos [approximately 350 pounds]. He was just trying to do his best there."

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Björnsson -- who stands 6-foot-9 -- played The Mountain for five seasons of Game of Thrones, but outside of Westeros, he's known for his illustrious strongman career. His list of accomplishments includes winning the Arnold Strongman Classic, Europe's Strongest Man and even the World's Strongest Man competition. In May 2020, he also set a new world record by deadlifting 501 kilograms (1,105 pounds). However, it's worth noting this feat was done in his home gym and not during an official competition, causing friction among diehard fans of strongman and powerlifting.

Soon after his milestone deadlift, Björnsson began rapidly shedding weight (he's lost over 100 pounds) to prepare for a boxing match with fellow World's Strongest Man winner Eddie Hall. His first exhibition match took place in January 2021 when he competed against the 217-pound Steven Ward. At the time, he weighed 344 pounds and was declared "The first TITAN WEIGHT fighter in history."

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Björnsson and Hall's long-awaited boxing match was scheduled to take place in September, but Hall suffered a bicep injury and the aptly titled "Heaviest Boxing Match in History" was postponed to 2022.

Source: YouTube, via BJJEE