France international defender Axel Disasi has joined Chelsea from AS Monaco on a six-year contract for 45m Euros (£38.57m).
Disasi, 25, offers defensive cover at Stamford Bridge after an knee injury sustained by Wesley Fofana.
He played in all 38 of Monaco's Ligue 1 games last season.
"I am really proud to be able to be a part of this great family," Disasi told Chelsea's website.
"I hope to achieve very big things here. To win titles. I will do everything I can to achieve those objectives. I am very ambitious."
Source: BBC