Chelsea signed Spain winger Juan Mata from Valencia for an undisclosed fee on Wednesday.
Mata agreed a five-year contract with the Premier League club after passing a medical and then trained with his new team-mates for the first time.
"Juan Mata completed his transfer from Valencia today, and will be available for Saturday's game against Norwich having already trained with the squad at Cobham earlier," a statement on the club's website confirmed.
Mata is Chelsea manager Andre Villas-Boas's fourth signing following the arrivals of Spanish midfielder Oriol Romeu, Belgian striker Romelu Lukaku and young goalkeeper Thibaut Courtois, who has since joined Atletico Madrid on loan.
The 23-year-old is believed to have cost Chelsea around £23.5 million as the Blues beat London rivals Arsenal and Tottenham to his signature.
Mata admitted former Porto boss Villas-Boas's commitment to an entertaining style of play was the main reason why he chose to join Chelsea after four years with Valencia.
"Villas-Boas is someone who won almost everything last year (with Porto) and we are both here with the idea of winning lots this season," Mata said.
"He said he wanted Chelsea this season to play more attacking football and that I would be a big part of that.
"The plan is that I can play on either flank or even in the middle playing in between the lines of midfield and attack.
"I want to adapt as quickly as possible to my new surroundings, my colleagues and this league, and I would love to win a trophy in my first season. If it can be the Premier League then great.
"Right from the first moment there have been good feelings all around me. Training has been great and the players are a great group to train with.
"Valencia was a big club but I have left to join a bigger club and it is all about the opportunity to win trophies and I have that here."
Mata has 11 caps for Spain and captained the Spanish Under-21s to victory at this year's European Championships and he admitted he spoke to compatriot Fernando Torres about Chelsea prior to the move.
Torres has struggled since joining Chelsea from Liverpool in January, but the £50 million striker still told Mata that Stamford Bridge was a good place to play.
"Fernando got me excited about the thought of coming here," Mata said.
"He said it would be good for me here and that me and him together could be good. I also talked to my family and friends about it as well."