The new England Lions off-spinner's Middlesex teammate, Jack Davies, has also extended his deal at the county
Josh De Caires has extended his contract with Middlesex, committing to the club until the conclusion of the 2025 season.
The 21-year-old allrounder has been part of the club's set-up since Under-10 level and signed his first professional contract in 2020.
De Caires made his debut for Middlesex's first team in all formats during the 2021 season and has made 34 appearances across formats.
He made a significant impact in LV= Insurance County Championship Division One, claiming career-best figures 8 for 106 against Essex at Chelmsford and taking 7 for 144 against Hampshire at the Ageas Bowl.
Those performances helped earn him a call-up to the England Lions squad for a three-week training camp in the UAE in November and December.
De Caires' heroics with the ball were not enough to prevent Middlesex dropping into Division Two (Alex Davidson/Getty Images)
"I’m really grateful to be given the opportunity to continue to represent Middlesex for the next couple of years," said De Caires, the son of ex-England captain Michael Atherton. "I look forward to trying my best to hopefully contribute towards success for the club next year and in the future."
Middlesex director of cricket Alan Coleman added: "Josh has been exceptional this year and has really stepped up to fulfil an important role for Middlesex that prior to this season was pretty alien to him.
"Coming into the side as a batter two years ago, it is a testament to how hard Josh works at his game, that he has been able to continue to develop his batting, whilst also working closely with the coaching staff to develop his off-spin.
"He is now an important part of this Middlesex side, has a really bright future ahead of him, and thoroughly deserves the opportunity he has earned to show the England selectors exactly what he can do, having been selected to tour to the UAE next month with the England Lions."
Jack Davies, the 23-year-old batter, has also extended his contract until 2025. The left-hander featured regularly in the T20 Blast and was involved towards the end of Middlesex's doomed fight for Championship survival.
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