Sunderland have completed the signing of French centre-back Jean-Yves Mvoto from Paris St-Germain.
The 19-year-old defender has signed a three-and-a-half year contract at the Stadium of Light.
Manager Roy Keane told the club's official website: 'Jean is one for the future.
'We've seen a lot of him and he's a strong centre-back who will be a good addition to our squad.'
The Black Cats have agreed an undisclosed compensation package for the 6ft 4in France Under-19 international, who said: 'This is a big opportunity for me, I'm pleased to be at Sunderland.'
Keane has already managed to land Manchester United defender Jonny Evans on loan until the end of the season, but has up to four more players in his sights.
His pursuit of Reading midfielder Stephen Hunt has resulted in a series of unsuccessful bids.
Sunderland were also linked with a £2million swoop for Blackburn striker Jason Roberts.