Watford have completed the signing of Gerard Deulofeu from Barcelona for an initial £11.5m fee.

The club could owe Barcelona up to £3.5 million in add-ons depending on how successful Deulofeu is at the club in the coming seasons.

There is also a percentage of future transfer fee owed to Barcelona as part of the deal, should Watford sell him at any point during his initial contract.

Deulofeu was on loan at Watford this past season, where he played in seven games and got a solitary goal.

"We are very pleased to welcome Gerard back to Vicarage Road and thank FC Barcelona for their part in concluding this deal," said Watford chairman and chief executive Scott Duxbury in a statement.

"Our ambition to succeed and grow in the Premier League remains as strong as ever."