Chelsea signed Portugal midfielder Raul Meireles from Liverpool in the final moments before the transfer window closed on Wednesday.
Blues boss Andre Villas-Boas moved quickly to snap up Meireles after his club's £40 million bid for Croatia midfielder Luka Modric was rejected by Tottenham.
Meireles had to hand in a transfer request to force through the deal in time for the 2200GMT deadline and he will fill the gap in Chelsea's squad left by the departure of Israel midfielder Yossi Benayoun to Arsenal.
"Chelsea Football Club is delighted to announce the signing of Raul Meireles from Liverpool on a four-year contract," a statement on the club's website confirmed.
Meireles arrives at Stamford Bridge, for a fee believed to be around £12 million ($19.4 million), after just over a season at Liverpool in which he made 44 appearances for the Reds.
The 28-year-old started this season on the bench for Kenny Dalglish's side and Villas-Boas was able to persuade him that his first-team prospects were stronger at Chelsea than on Merseyside.