Hause's move to Vicarage Road was originally lined up as part of the talks involved in taking striker Ismaila Sarr to Villa Park for £25m.

That fell through and is unlikely to be resurrected before the window closes on 1 September, but Hause has still moved.

Hause joined Villa from Wolves, initially on loan, helping them to win promotion to the Premier League under Dean Smith before signing a more permanent deal.

He becomes new Watford boss Rob Edwards' seventh summer signing - and the second Villa player to move to Hertfordshire on a season-long loan after striker Keinan Davis.

Watford sit second in the Championship, a point behind leaders Sheffield United, after an unbeaten start in their first five league games under Edwards.