Fikayo Tomori has committed his long-term future to Chelsea by signing a five-year contract.
The defender, 21, has played 16 times for the Blues during a breakthrough campaign which has seen him earn his first England cap.
Tomori's new deal keeps him at the London club until the summer of 2024.
"It's obviously a very proud moment for myself and my family," Tomori, a graduate of Chelsea's academy, said on the club website.
"I've been at the club since I was seven years old so I don't really know much else other than Chelsea.
"The club has been so good to me, looking after and developing me during that time into the player and the person I am today.
"It's a dream come true to sign a new five-year contract. I'm really happy the club have shown this faith in me and I'm just excited to carry on."
Tomori starred for Frank Lampard during a loan spell with Derby last season. And, after he took the managerial reins at Stamford Bridge, Lampard wasted no time in promoting Tomori to the first team.
He scored his first goal for Chelsea during a 5-2 win over Wolves in September before going on to feature in the Champions League.
England manager Gareth Southgate then rewarded Tomori with his first call-up to the senior squad in last month's Euro 2020 qualifying victory against Kosovo.
Chelsea director Marina Granovskaia added: "We are very happy to see another fantastic young player come through from our academy into the senior team.
"Fikayo has been with us since he was seven years old and has contributed to many Chelsea successes at youth level.
"Having enjoyed an impressive loan spell at Derby last season, Fikayo had a strong start to this campaign and we are enjoying seeing him grow into a key player for us. We are delighted he has committed to the club for the coming years."