Defender Adrian Mariappa has made his return to Watford on a three-year contract.
Mariappa has spent the last three years at Crystal Palace, but he was released by the Eagles after making just three appearances in the Premier League last season.
However, he has now been given the opportunity to remain in the top flight with former club Watford as they continue to strengthen their squad at Vicarage Road.
In his first spell with the club between 2005 and 2012, the 29-year-old made a total of 247 appearances in all competitions.