12 months after he signed for Watford, Brazilian winger Richarlison has been reunited with Marco Silva after he signed for Everton in a deal thought to be worth up to £50m.
Richarlison turned out 41 times for the Hornets, scoring five times.
Elsewhere injury plagued centre back Tommie Hoban will spend the new campaign with Aberdeen and could also get a taste of European football as the Dons are competing in the Europa League this season. Watford could recall Hoban in January if required.
Finally Moroccan Nordin Amrabat brings a two year spell at the club to a close with a permanent transfer to Saudi Arabian side Al-Nassr FC. Amrabat signed from Malaga in January 2016.