The 19-year-old defender has signed a three-and-a-half-year contract with the Bhoys.
“Thomas is a young player we’ve watched for a while and we’re delighted to bring him to the club. He’s only 19 but has had good experience in the Norwegian league,” Celtic boss Tony Mowbray told the club’s official website.
“We’ve had a chance to have a look at him in recent days at Lennoxtown and he’s shown up well. He has all the physical attributes and personality to be a success at Celtic.
“Thomas has a bright future and will be training with the first-team squad, and competing for a place in the side.
“Like Josh Thompson and Milan Misun, Thomas is a big part of our future plans in defence. We are bringing these talented players to the club in order to ensure the foundations are in place for the coming years.”
