Porto have announced the permanent signing of Watford wing-back Miguel Layun.
Layun joined Watford in January 2015 but spent last season on loan with Porto.
The Portuguese side have now made the deal permanent, paying a reported six million euros.
A statement from Porto read: "The Mexican was on loan from Watford, but our club reached an agreement with the English club. If Layun was already a player in the style of Porto, now he will have a contract with Porto."
There has been speculation Layun could be sold on to Real Madrid this summer.