The Brazil midfielder has been targeted by the Blues for quite a while and the deal went through right after he passed a medical at Stamford Bridge.

Twenty-three-year-old Ramires, who penned a four-year contract, will not be available for Chelsea's Premiership opening game against West Brom on Saturday.

He will join up with his new teammate next week.

"Every player in the world would love to play for Chelsea and it's a great opportunity that was given to me," Ramires told Chelsea's official site.

"I will give my best to repay this chance, and I am very happy."

Ramires had a season to remember with Benfica and is tipped to raise eyebrows in England.

"He is a fantastic player, a fantastic midfielder, he is very young and will be the future of the Brazilian national team, and I hope he will be the future of Chelsea," said boss Carlo Ancelotti.