Costel Pantilimon has been recalled from his loan at Deportivo de La Coruña and will now spend the rest of this season with Nottingham Forest.
The 30-year-old goalkeeper has made a loan move to the Championship side after appearing seven times in Spain.
Official | Hornets Loan Ndong
Highly-rated midfielder Didier Ndong has agreed a loan move to Vicarage Road, the Hornets are pleased to confirm.
The 23-year-old will spend the remainder of the 2017/18 season with Watford, while the club also have the option on a permanent transfer in the summer.
Ndong joins from Sunderland, who paid a club record transfer fee to secure his services in August 2016.
In total he played 54 times for the Black Cats, including 31 appearances in the Premier League last season.
Having started his senior career with Tunisian club CS Sfaxien, Ndong switched to Lorient three years ago and won plenty of admirers in Ligue 1, playing 54 times for the French side before his move to England.
He has also represented his native Gabon on the international stage on 17 occasions.