Chelsea signed Portugal midfielder Maniche on loan from Dynamo Moscow on Wednesday, the English champions said.
The 28-year-old former Porto player has joined coach Jose Mourinho's Premier League leaders until the end of the season, the English side said on their official web site.
Maniche, who won the European Cup with Porto under Mourinho in 2004, is eligible to play for Chelsea in the Champions League because he has not played in Europe for Dynamo.
He joined Dynamo in May 2005 for a Russian record transfer fee of 16 million euros (11 million pounds), along with Porto team mate Costinha.
Atletico Madrid were linked last month with Maniche, who was unsettled in Moscow.
Maniche, who also worked under Mourinho at Benfica in 2000, will increase Chelsea's midfield options during a spell when they will be without Michael Essien.
The Ghana international will join his country for the African Nations Cup in Egypt later this month if he recovers from an ankle injury he sustained in Chelsea's 3-1 win at West Ham United on Monday.
Maniche was a key member of the Portugal team that reached the final of Euro 2004 in their home country.