Dunbar died suddenly at his home in Belfast on Tuesday, Christmas Eve. His death is reportedly not being treated as suspicious by authorities. In addition to serving as the body double for Theon Greyjoy on Game of Thrones, he also had roles in shows such as Derry Girls and Line of Duty.
"Andrew was an actor who was also a stand-in as Theon on GoT," Allen wrote on his Instagram Story. "Extremely shocked and saddened to hear of his passing."
"To lose a loved one so young, I can only imagine what his family are going through," he added. "RIP Andrew xxx."
In an earlier statement, a spokesperson for The Extras Dept. said the team had "many fond memories of the years Andrew worked with us."
"He was so versatile we could cast him in anything, he was such a talented performer he would always end up being featured, and he was so adored that he was always requested by productions again and again," the statement continued.
The statement concluded: "He'll be remembered in his roles as a Stark and Theon Greyjoy’s Double on Game of Thrones, a corrupt police officer on Line of Duty, the poor fella cornered by Colum on Derry Girls, and a Rebel on Krypton to name a few. But most of all he’ll be remembered by his kind soul and infectious personality. Thank you for all you did for us Andrew. We will miss you dearly."
See more on stars we've lost recently in the video below.