Quique Sanchez Flores has been appointed Watford's new head coach - half an hour after Javi Gracia's sacking was confirmed.
Gracia's departure was announced on Saturday with the Hornets bottom of the Premier League table after taking one point from four games.
He led Watford to the FA Cup final and an 11th place finish in the Premier League last term but was dismissed despite captain Troy Deeney publicly backing him to continue.
Watford wasted no time in announcing the club's former coach Flores will be back in the dugout at Vicarage Road for their game against Arsenal following the international break.
Flores spent the 2015-16 season in charge of Watford, leading them to the FA Cup semi-finals and a mid-table league finish.
Since leaving the Hornets, he has had spells at Espanyol and Chinese Super League side Shanghai Shenhua.
Flores' return is the 11th coaching appointment made by Watford since Malky Mackay's departure in June 2011.
Walter Mazzarri and Marco Silva, who is now in charge of Everton, are among their recent bosses.