The Czech Republic international has had two successful loan spells with the Hornets but has now made his move from Udinese to Vicarage Road less temporary by putting pen to a five-year contract.
Striker Vydra scored 16 goals as Watford gained promotion from the Championship last term to take his tally to 38 for the Hertfordshire outfit after his 22-goal haul in 2012/13.
OFFICIAL: @vydra_92 signs permanent five-year deal with #watfordfc. Info: http://t.co/XAwkgOUVKDpic.twitter.com/OmwzrvBNia
— Watford FC (@WatfordFC) July 1, 2015