Sheffield United defender Matthew Kilgallon has become Sunderland boss Steve Bruce's first signing of the January transfer window.
Kilgallon, 26, has signed a three-and-a-half year deal with the Black Cats after the two clubs agreed an undisclosed fee.
Speaking to the club's official website after tying up the deal, manager Bruce said: ''Matthew is a very talented defender and has been coveted by a number of top-flight clubs recently, so I'm very pleased to have brought him here.
"He will add to our options across the back ahead of some very important games. I'm sure he'll prove to be a great signing for the club."
The player will be unavailable for this Saturday's trip to Portsmouth as he has already appeared in the FA Cup for Sheffield United this season.