Millwall have signed Japhet Tanganga from Tottenham Hotspur on a permanent transfer.
The 25-year-old made 18 appearances on loan at The Den last season as the Lions finished 13th in the Championship.
Tanganga has signed a “long-term” deal, external after his Tottenham contract expired this summer.
He made 50 senior appearances for Spurs after coming through the club’s academy.
“He was the number one target over the summer,” Millwall head coach Neil Harris told the club’s website.
“He has fitted perfectly in the dressing room, the fans have taken to him immediately with his performances and the way he plays the game with a big heart.
“He’s just a very, very good player.”
Tanganga is Millwall’s second summer signing, following the arrival of Macaulay Langstaff from Notts County on Monday.