Winger Grady Diangana has signed a new deal with West Ham until 2025.
The 20-year-old follows fellow Irons academy graduate Declan Rice in agreeing a contract extension at the Premier League club.
Diangana has broken into Manuel Pellegrini's first-team squad after made an impressive senior debut in the 8-0 Carabao Cup win over Macclesfield, scoring twice.
"I am very excited to know that my future is here for the next six years. I'm really excited to show the world and the fans at London Stadium what I can do," said Diangana, who has made 15 first-team appearances this season.
"It's a challenge. I want to prove to everyone what I can do. I want to show everyone what I can do and why I deserve to be here.
"I'm very grateful to everyone in the Academy. To every manager and all my team-mates that I've played with since I've been here."
Diangana, who has been with the Hammers since the age of 10, added on the club website: "It's really a journey because you get the highs and you get some lows, but all in all it makes you become a better player and a better person."
Pellegrini is confident Diangana can continue his progress with the Irons.
"He has made great progress since the beginning of the season and deserves the opportunity he has been given," the West Ham boss said.
"As I have said previously, I have trust in Grady because he is a clever, intelligent player who always has a good solution with the ball.
"Like Declan Rice, he is still a young player with many years of football ahead of him and still much to learn about the game.
"However, if he keeps working hard and showing the dedication and willingness to learn that I have seen this season, then he can have a very successful career."
Pellegrini added: "I know that, for West Ham, the development of our young players through the academy is a very important part of the club's heritage and tradition.
"Grady is one of a number of good young players we have coming through and it is a very encouraging sign for us."
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