Chelsea have signed Russian international Yuri Zhirkov from CSKA Moscow for a reported £18m fee, BBC reported.
The 25-year-old left-back, who has played 28 times for Russia, came to prominence during Euro 2008 when the national side reached the semi-finals.
Zhirkov, who can also play in midfield, has joined on a four-year deal.
New Chelsea boss Carlo Ancelotti confirmed the signing at first official news conference saying: "Zhirkov is naturally on the left."
He added: "I think he can do all the work and can play in defence and in between."
The Russian utility player is Chelsea's third signing of the summer, following the arrivals of goalkeeper Ross Turnbull and striker Daniel Sturridge.
During his time with CSKA Moscow, Zhirkov helped the Russian club win the Uefa Cup, scoring the second goal in the 3-1 win over Sporting Lisbon.
Zhirkov flew to London on Sunday and underwent a medical before completing his transfer.
Ancelotti refused to confirm Deco and Ricardo Carvalho would be leaving Stamford Bridge despite the pair being heavily linked with Inter Milan.
The former AC Milan boss said: "Carvalho and Deco are Chelsea players.
"If in the future a player wants to go they have to speak with the club and we take the right decision for the player and for us."
Ancelotti also insisted he wanted John Terry to be his captain after the England skipper was heavily linked with a move to Manchester City.