Hoskins has struggled to get regular spot in Watford's first-team

Hoskins, 21, joined Watford from Rotherham in January but has been restricted to just a dozen appearances for the Championship leaders.

Millwall boss Willie Donachie told his club's official website: "He's like a young Kenny Dalglish - he's that sort of player.

"Will played against us last season and scored two so we know about him. He's a very bright, intelligent player."