The Hornets confirm Abdoulaye Doucouré has joined Everton on a permanent transfer.
The midfielder made 141 appearances for Watford since arriving from Rennes in 2016, scoring 17 goals.
Doucouré earned the club's Player of the Season award for his fine displays during the 2017/18 campaign, and was also picked as Players' Player of the Season.
The 27-year-old now moves to Goodison Park for an undisclosed fee.
Watford FC thanks Abdoulaye for his contribution to the club and wishes him well in the future.