The former Tottenham defender moves to Vicarage Road for a reported fee of £4 million and has expressed his desire to help the Hornets improve on last season's 13th-placed finish
Watford has confirmed the signing of center back Younes Kaboul from Sunderland on a three-year deal.
The 30-year-old has moved for a reported four million pounds ($5.2M) after Sunderland announced on Thursday that he had informed them of his desire to move to Vicarage Road.
"Experienced French international defender Younes Kaboul has today completed a permanent transfer to the Hornets," Watford announced in a statement.
"The 30-year-old centre-half has signed a three-year contract after joining from fellow Premier League club Sunderland.