Watford have signed striker Britt Assombalonga on a six-month contract, with an option for a further year.
Assombalonga made four appearances for the Hornets early in his career before spells with Peterborough, Nottingham Forest and Middlesbrough.
He is a DR Congo international and is the fifth signing made since the January transfer window opened.
The club has not disclosed whether any fee was paid for Assombalonga.