Chelsea have signed Senegal goalkeeper Edouard Mendy from French club Stade Rennes on a five-year deal, the Premier League side said on Thursday.
Financial details of the transfer were not disclosed but British media reported Chelsea paid around 22 million pounds ($28.01 million) for the 28-year-old who had three years left on his Rennes contract.
"I am so excited to be joining Chelsea. It's a dream for me to be a part of this exciting squad and to work with Frank Lampard and all of his coaching staff. I look forward to meeting my team mates and can't wait to get started," Mendy told the club's website.
Mendy played 33 games in all competitions for Rennes last season as they finished third in Ligue 1 to qualify for the Champions League.
France-born Mendy chose to represent Senegal - the country where his mother was born - at international level and has eight caps.
He becomes the second goalkeeper to make the switch from Rennes to Chelsea following Petr Cech's move in 2004.
"As soon as Cech and our technical team identified Edouard as the most suitable goalkeeper to complement our existing group, there was only one player we wanted to bring in," Chelsea director Marina Granovskaia said.
"Edouard arrives following a season of real success with Rennes, he is ambitious for more, and we welcome him to our club."
Mendy's signing follows the arrivals of full back Ben Chilwell, striker Timo Werner and wingers Hakim Ziyech and Kai Havertz, with the overall outlay totalling more than 200 million pounds.
The London club also signed defenders Thiago Silva and Malang Sarr on free transfers.
Chelsea's decision to boost their goalkeeping options follows Spaniard Kepa Arrizabalaga's dip in form since last season, with his latest error coming in their 2-0 defeat by champions Liverpool last Sunday.
Chelsea, who finished fourth last term to qualify for the Champions League in manager Frank Lampard's first campaign in charge, face West Bromwich Albion in the Premier League on Saturday.