Sunderland have signed Ivory Coast defender Lamine Kone from French side Lorient for an undisclosed fee.
The France-born 26-year-old has signed a four-and-a-half-year contract with the Premier League strugglers.
"He is big and strong, attributes you need to play in central defence in the Premier League," Sunderland manager Sam Allardyce told the club's website.
Allardyce announced on 8 January that attempts to sign Kone had "broken down".
But with the deal now completed, Allardyce said: "Strengthening our defensive options was a priority for us and Lamine is a player that has impressed me when I've seen him play.
"His arrival will give us healthy competition for places in a key position."
Sunderland are 19th in the league, four points from safety with 15 games remaining. Their next league game is at home to second-placed Manchester City on 2 February.
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