Chelsea have completed the signing of France Under-21 international central defender Wesley Fofana from Leicester City, the two clubs announced on Wednesday.
Fofana, 21, has signed a seven-year deal at Stamford Bridge, the London outfit said.
The transfer fee is undisclosed but reports in the UK said Chelsea would pay their Premier League rivals £70 million plus bonuses for the former Saint-Etienne player.
“Wesley is a hugely promising defender who has already proven his quality in the Premier League at a young age,” said Chelsea chairman Todd Boehly.
“We are delighted we were able to bring one of Europe’s most exciting talents to Chelsea and further strengthen that area of our squad, both for this season and many more to come.”
Fofana is the latest player signed in this transfer window to bolster Chelsea’s defence, following the arrivals of Kalidou Koulibaly from Napoli and Marc Cucurella from Brighton and Hove Albion.