Tierney is only 19 years of age, but the teenager has already established himself as an important player in the current Celtic side.
The talented and promising youngster has already played twice for the Scotland national football team.
The left-back is one of the best in his position in the Scottish Premiership and is one of the best young players in Scotland.
Former Celtic defender Boyd has been impressed with Tierney and has praised the progress that he is making at the moment.
“Kieran’s making stunning progress,” Boyd told Herald Scotland. “I was going to say the goal he nearly scored at the weekend was reminiscent of me - but it was more like Archie Gemmill.
“The way he can beat players, he’s turning in to an auxiliary winger almost. He’s a throwback. You see a lot of modern full backs who love to get forward, but Kieran can defend as well.
“He loves a tackle so he’s got everything in his locker. He is adding to the overall quality at the club at the moment.”
Former Chelsea and Scotland international winger Pat Nevin has also been impressed with Celtic defender Tierney.
Nevin has compared the teenage left-back to Celtic legend Danny McGrain, and has said that the youngster is astonishing.
“What I also don’t say lightly is that he actually does remind me a bit of Danny McGrain,” Deadline News quotes Nevin as saying to BBC Scotland.
“I really hesitate before saying that because Danny was one of the greatest players I’ve ever seen, certainly in Scottish football but also world football. But Kieran Tierney is just astonishing just now.”
Celtic are at the top of the Scottish Premiership table at the moment with 22 points from eight matches, four points clear of second-placed Aberdeen with a game in hand.
The Bhoys will take on Borussia Monchengladbach at Celtic Park in Champions League Group C on Wednesday evening.