Chelsea continued their spending spree by signing Portugal defender Ricardo Carvalho from Porto on a three-year contract for around 30 million euros ($36.50 million) on Tuesday.
The 26-year-old Carvalho will link up with his former coach Jose Mourinho at the English premier league club.
"Ricardo Carvalho tonight signed a three-year contract with Chelsea and will jet out with (chief executive) Peter Kenyon to join the squad in the U.S. tomorrow (Wednesday)," Chelsea said on their website.
Carvalho played a key role in Porto's Champions League-winning campaign under Mourinho last season and Portugal's run to the Euro 2004 final. He has 10 international caps.
"Ricardo is a player that fits our profile. We have filled the last (squad) opening at centre-back and we now arrive with four excellent players in this position," said Mourinho, who also has John Terry, William Gallas and Robert Huth to call upon in the middle of the defence.
Carvalho is Chelsea's seventh major signing under Mourinho, who replaced Claudio Ranieri as coach last month.
He joins Ivory Coast striker Didier Drogba, Dutch winger Arjen Robben, Czech goalkeeper Petr Cech, Serbia and Montenegro striker Mateja Kezman, Portugal midfielder Tiago Mendes and Portugal defender Paulo Ferreira.
Carvalho's arrival brings Chelsea's spending since the end of last season to around 100 million pounds ($185 million) and to more than 200 million since Russian billionaire Roman Abramovich took control of the club a year ago.
"We are delighted that Ricardo has signed with us as he was being chased by top clubs all over Europe," said Kenyon.
"He proved during Euro 2004 and in the past two seasons with Porto that he is one of the top centre-backs in the game."
Chelsea, who were premier league runners-up last season and reached the Champions League semi-finals, face Manchester United in their first game of the new season on August 15 at Stamford Bridge.