Sunderland midfielder Didier Ndong has joined Watford on loan, the Hornets have announced.
The 23-year-old Gabon international will remain with Javi Gracia's side until the end of the season, when the Premier League club will have an option to make the move permanent.
Ndong joined the Wearsiders in 2016 and made 54 first-team appearances, with his last outing in January ending with his sending-off at Cardiff.
Watford have loaned Costel Pantilimon to Nottingham Forest after his loan spell at Deportivo was cancelled.
The LaLiga club confirmed the end of the goalkeeper's temporary switch and he has now joined Championship side Forest for the rest of the campaign.
Winger Isaac Success has also departed Vicarage Road having moved to Malaga on loan until the end of the season.
The 22-year-old has played 20 times for the Hornets and scored once since joining from Granada for around £12.75m in 2016.
The winger had only played once this season and was yet to feature in the Premier League.