The France defender has signed a one-year deal at White Hart Lane after quitting their north London rivals this summer.
Smiles better: William Gallas poses with the Tottenham shirt
Gallas, 33, linked up with his new team-mates for his first training session at Spurs' training HQ in Chigwell.
He later posed for pictures with the famous white shirt - a sight that would have stunned Gunners fans a few weeks ago.
Gallas will now compete for a place in the backline with Michael Dawson, Ledley King, Younes Kaboul, Sebastian Bassong and Jonathan Woodgate.
Ex-Gunner Gallas crosses north London divide to complete Spurs moveClub-by-club Premier League guide to every transfer deal in summer 2010TOTTENHAM HOTSPUR FC