Tottenham have confirmed the signing of former Arsenal defender William Gallas on a one-year contract.
Gallas, out of contract after leaving the Gunners, had only to complete a medical and agree personal terms.
Spurs have also retained the right to extend the contract of the 33-year-old, who also played in the Premier League for Chelsea, for another season.
Gallas will join a select band of players who have turned out for Arsenal and Tottenham and the move is likely to be controversial with some fans of both north London rivals.
But Spurs boss Harry Redknapp said on Friday: "It's all cobblers. What's he done? It's not the Yorkshire Ripper I'm signing, is it? He's a footballer, he plays football."
France international Gallas was part of the Chelsea side which won back-to-back Premier League titles after moving from Marseille. He joined Arsenal in 2006 and captained the team in the 2007-08 season.