"It is with great pleasure that I now get to call Kelsey Morgan Henson my wife!" Björnsson wrote in a post on Instagram.
"I get to hold this beautiful woman through thick and thin for the rest of our lives!" he added. "I'm so excited for all of the future adventures we will tackle side by side."
Henson also posted about the wedding, gushing over her new husband and the love they share.
"Looking forward to pulling this big guy around for the rest of my life," she wrote. "[Hafþór Júlíus Björnsson,] I love you now and forever and promise to stand by your side through all that life throws at us. I love you baby!"
Many of Björnsson's fans have commented on the couple's nuptials, with most congratulating them on tying the knot.
"Congrats. A good woman will make any man better," someone else commented. "They humble you and make you a better person."
"OMGGG I've been following you guys ever since you guys first got together," another fan exclaimed. "This is absolutely precious and congratulations to both of you!!!"
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Björnsson and Henson first began dating in 2017. They reportedly met when Henson asked to take a photo with the Game of Thrones star at a bar where she was employed. The two realized they had chemistry and struck up a romance.
The two do not have any children together, but Björnsson has a daughter from a previous relationship.
While he most well-known for his role as Ser Gregor Clegane ("The Mountain") on Game of Thrones, Björnsson is also an accomplished bodybuilder and weightlifter.
In May, he traveled to the Philippines to compete in the World's Strongest Man competition which he subsequently won. The win was a big achievement for Björnsson, as he lost the 2017 World's Strongest Man competition by just one point after a referee cited him for breaking a rule that he contented he did not break.
There does not appear to be any word on whether or not he will return to the competition in 2019 to defend his title.