Black Cats wrap up Matthews deal
Sunderland have completed the signing of Celtic right-back Adam Matthews for a fee of £2million.
The Black Cats confirmed the deal on Friday night, a little more than 24 hours after agreeing a fee with the Scottish champions.
Head coach Dick Advocaat said on the club's website: "We know that we need quality players to improve competition for places in the side, so Adam is a welcome addition to our squad and we are very pleased to welcome him to Sunderland."
Matthews, who joined Celtic from Cardiff in 2011, had been linked with a number of clubs and at one point appeared set for a return to his native Wales.
He made 42 appearances for the Bhoys last season and picked up a fourth Scottish Premiership winners' medal in the process.
"Adam is a player we have been tracking for some time," Sunderland sporting director Lee Congleton said. "Even though he is only 23 years old, he has a wealth of experience, and I am sure he will continue to improve under the leadership of Dick Advocaat."
The arrival of the Wales international continues a busy few days for the Wearside club, who completed a permanent deal for Liverpool defender Sebastian Coates on Wednesday night and then tied up key midfielder Lee Cattermole with a five-year contract extension.
In addition, they are understood to be maintaining interests in Zenit St Petersburg's Belgium international defender Nicolas Lombaerts and Dutch striker Jeremain Lens, who plays for Dynamo Kiev.