Arsenal have signed Celtic defender Kieran Tierney in a deal believed to be a Scottish record £25m.

The Gunners have been chasing the 22-year-old throughout the summer, having two bids rejected before finally sealing the deal on deadline day.

The left-back will wear the number three shirt at the Emirates and has signed a long-term deal.

Arsenal boss Unai Emery is delighted to get his man, saying: "We're delighted Kieran is joining us.

"He's a very talented player who will continue to improve.

"He increases our options defensively and I look forward to him joining our group."

Tierney - a boyhood Hoops fan - came through Celtic's academy and won eight trophies at the club after making his first-team debut in 2015.

He made 170 appearances for Celtic and has played 12 times for Scotland.