Ben Foster has signed a new two-year deal to remain at Watford until 2022.
The 37-year-old goalkeeper, a Premier League ever-present this season, would have become a free agent with his previous contract due to expire this summer.
Foster, who has eight England caps to his name, moved to Watford on a permanent deal from West Brom in 2018 and has made nearly 150 appearances in his two spells with the Hornets.
The goalkeeper first played for Watford almost 15 years ago when he joined the club as a youngster on loan from Manchester United before moves to Birmingham and then West Brom.
Foster replaced Brazilian Heurelho Gomes as the club's number one when he signed for the club two seasons ago.
Mariappa, Holebas and Gomes to see out season as talks on new deals continue
The Premier League club have also announced that the three other players whose Watford deals were set to expire this summer - Jose Holebas, Heurelho Gomes and Adrian Mariappa - have each agreed contract extensions to cover the delayed finish to the 2019/20 campaign.
Mariappa - like Foster - is also in his second spell at the club at 33 and has featured in 10 matches since the appointment of Nigel Pearson as head coach in December.
Holebas, who joined the club from Roma prior to the start of Watford's first season back in the Premier League in 2015, has been limited to 13 appearances this season, having previously been a first-team regular.
Gomes, who has been at Watford since 2014, turned 39 in February has played in just three games this season, all in the League Cup.
Talks over new deals for the trio continue to be held with the club.
Watford live on Sky on June 25
When the Premier League restarts, Watford's second game back - against Burnley - will be live on Sky Sports.
After their match with high-flying Leicester on June 20, the relegation-threatened Hornets face Burnley on a Thursday night - a game live on Sky's free-to-air Pick channel - and Southampton on June 28, also live on Sky Sports.
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Sky Sports will show 64 live Premier League games when the season resumes. In addition to the 39 matches already scheduled to be broadcast exclusively live on Sky Sports before the coronavirus interruption, 25 more matches will be available on both Sky Sports Premier League and Sky's free-to-air Pick channel, allowing the whole nation to be part of the return of live sport.
Free-to-watch highlights of every remaining Premier League game this season will be available from shortly after the full-time whistle on the Sky Sports website, Sky Sports app and Sky Sports Football YouTube channel.