Sunderland have completed the £5million signing Lamine Kone at the third time of asking after a month-long pursuit of the centre-half.
Kone has been on Sunderland's radar throughout the January transfer window, yet a deal for the Ivory Coast international has proved to be problematic after falling through on two previous occasions.
Sunderland had abandoned their interest in the 26-year-old last week and Kone looked set to remain at French club Lorient.
However, when Sunderland entered into talks with Sporting Lisbon over the sale of Sebastian Coates, they revived their interest in fellow centre-half Kone and saw a £5m bid accepted by Lorient on Tuesday.
Kone has now completed the formalities of his move to Sunderland and has penned a four-and-a-half year deal at the Stadium of Light.
Sunderland boss Sam 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.
"He is big and strong, attributes you need to play in central defence in the Premier League, and his arrival will give us healthy competition for places in a key position.”
Allardyce has been keeping tabs on Kone since his tenure as West Ham boss and he made a personal check-up on the defender last month.
He will take the place of Coates in Allardyce’s ranks, with the Uruguayan on the verge of joining Sporting on loan until the end of the season, with a view to a permanent switch next summer.
Coates only joined Sunderland in a £2m move from Liverpool six months ago, yet he has failed to start in the Premier League during 2016, with veteran Wes Brown moving ahead of him in the pecking order.
Reports in Portugal have suggested that the permanent fee agreed for Coates could be worth more than £3m.
Sunderland are also hoping to strike a loan deal for ex-Newcastle United defender Debuchy, who is keen to leave Arsenal to play regular first-team football.
Debuchy wants to secure his place in the France squad for the summer’s European Championships and has not featured for the Gunners since November.
Aston Villa have been in talks over Debuchy throughout the window, but Sunderland are hoping to pip the Premier League’s basement boys to the 30-year-old.
Allardyce also remains keen to add another forward to his squad, with Sunderland continuing their efforts to land Swansea’s Andre Ayew.
Swansea have denied that Sunderland had made an improved bid for Ayew, yet the Ghana international remains one of Allardyce’s top targets.