Midfielder Adlene Guedioura has returned to Watford from Crystal Palace after signing a three-year contract.
The 29-year-old had two loan spells at Vicarage Road last season and returns on a permanent basis.
The Algeria international was the Hornets’ second signing of transfer deadline day after the capture of 19-year-old Belgian striker Obbi Oulare on a five-year deal from Club Brugge.
Watford said on their official website: “Watford FC are delighted to announce that Adlene Guedioura has completed a permanent return to Vicarage Road from Crystal Palace.
“The midfielder has signed a three-year contract and adds further quality and depth to Quique Sanchez Flores’ Premier League squad.”
Guedioura made 17 appearances and scored three goals in Watford’s promotion-winning campaign last term.
Oulare came through the academy ranks at Lille in France before moving to Brugge in 2013, where he scored nine goals in 39 appearances.
Midfielder Miguel Layun earlier joined Porto on a season-long loan from Vicarage Road.
The Mexico international joined the Hornets in January, helping them to promotion to the top flight, but now could be in Champions League action with Porto.