Chelsea's Ethan Ampadu has signed a new five-year contract at the club.
Ampadu, 18, who can play in defence or midfield, has made one Premier League appearance for Chelsea since joining from Exeter City in 2017.
The Welshman has featured seven times for the first team, mostly in cup games, and is yet to play for Maurizio Sarri's team this season.
He made his first international start earlier this month in the 4-1 win over the Republic of Ireland.
"We look forward to watching him develop into a key player for the club over the coming years," said Chelsea director Marina Granovskaia.
Ampadu made his senior Chelsea debut in the Carabao Cup in September 2017, becoming the first player born in the 21st century to start a game for the London side.
Cardiff City manager Neil Warnock says he plans to talk to Chelsea about signing Ampadu on loan in January.