Callum Hudson-Odoi has signed a new five-year contract with Chelsea.
The England winger's previous deal was scheduled to expire at the end of the season and he was widely linked with a move to Germany with Bayern Munich in January and again over the summer.
Hudson-Odoi spent the summer rehabilitating after rupturing his Achilles in April but recently returned to the pitch when he played for Chelsea's U23 side against Brighton.
"It's an amazing feeling," Hudson-Odoi said after signing his new deal alongside Chelsea director Marina Granovskaia.
"It's been a long wait but it's done now and I'm really happy about that. I've been a Chelsea player since I was eight and this is the right club for me to be at.
"I want to lift as many trophies as possible, win as many games as possible and contribute to as many goals as I can as well. As a team, we just want to work hard to achieve the best results we can. I'm delighted everything has been agreed and now I'm just looking forward to properly getting back."
Chelsea boss Frank Lampard, who made re-signing Hudson-Odoi a priority after becoming manager this summer, is delighted the deal has been finalised.
The 18-year-old became Chelsea's youngest England international last season, making two appearances for Gareth Southgate's senior side before suffering his injury setback.
"I have seen Callum come through and he's a fantastic talent," added Lampard. "He is going to be central for us on the pitch and that is the opportunity in front of him now.
"There are things as a young player that he will want to improve but he can be central to this team and for England. I want to work with him, I want to drive him forward and I want to improve him as a player.
"Callum can show, right here at Chelsea, the club he came through the Academy at, that he is going to be a world-class player because I truly believe that."
'London Calling' on Sky Sports
This weekend's Super Sunday will be focused on England's capital with 'London Calling' taking over Sky Sports. We'll have two games from London live and exclusive, starting over in the east of the city as West Ham host Manchester United with coverage starting on Sky Sports Premier League at 1pm and kick-off at 2pm.
This is followed by a jump across town to west London where Chelsea host Liverpool, with kick-off at 4.30pm at Stamford Bridge.
You can also follow both 'London Calling' games on Sky Sports' digital platforms with live blogs, match reports and expert analysis, plus in-game clips and match highlights shortly after full-time for free across all platforms - there is no need to be a Sky Sports subscriber. Full-time highlights will also be available on YouTube.