Hardest decision of my life: Kieran Tierney ready for Arsenal action after moving on from boyhood club Celtic
Kieran Tierney felt he had to take a step forward in his career and move to Arsenal after living his dream at Celtic.
The Hoops insisted they did everything possible to keep the left-back before selling him to the Gunners for £25million.
The 22-year-old had been at his boyhood heroes from the age of seven and was under contract until 2023 but, after making 170 first-team appearances and winning 10 trophies, his ambitions changed.
Tierney said: "It was the hardest decision in my whole life that I've had to make.
"I had to speak to my family and my close friends and my agent as well because it's a hard decision to leave a club that you love so much. People need to know that as well.
"I feel Arsenal is a massive club and it's a great opportunity for me as well. I'm delighted to be here.
"When I was younger, it was always Celtic. The ambition was Celtic and that was my dream when I was younger. But when you get older... I've done that, I've made my dream, I've lived my dream and I've loved every single minute of it.
"Now I just feel was the right time to take a step on. I feel this is a great opportunity for me."
The Premiership champions, who visit Ulsterman Stephen Robinson's Motherwell in the league tomorrow, confirmed the club-record fee to the stock exchange after Tierney became the most expensive Scottish footballer.
A statement on Celtic's official website read: "We did all we could to keep Kieran at Celtic. While the club did not need or wish to sell Kieran, this was an opportunity which Kieran very much wished to pursue and with the club having received a significant offer, we have agreed to the transfer.
"Kieran has been a big part of the club, coming through our academy and becoming a key first team player of real quality."
Manager Neil Lennon added: "This is an opportunity Kieran wanted to take and while we will be sad to see him leave, we wish Kieran all the very best for the future."
Lurgan-born Lennon will step up attempts to sign a new left-back before the Scottish transfer deadline on September 2.
Summer signing Boli Bolingoli had some shaky moments in Romania on Wednesday as Celtic drew 1-1 with Cluj in the first leg of their Champions League qualifier.
Lennon said: "We have new players coming in defensively, two new full-backs and Christopher (Jullien) coming in so it's a work in progress.
"But they have a very good goalkeeper (Scott Bain) behind them and he made a terrific save at an important part of the game," he added.