The Blues made their move for the 30-year-old midfielder after he was told he did not feature in Barcelona's future plans.

The Brazil-born player is the club's first signing since the appointment of Luiz Felipe Scolari as manager and he is believed to have cost around £8million.

Deco told Chelsea TV: "It is good for me to be here and first of all I am very happy to be here.

"I am sure I have come at the right time to do great things and be able to help Chelsea go back to the way it was and come back to being the first one, not only in England but also to win the Champions League that has been their dream for so long."

Deco's move will see him link up once again with Scolari, his national coach at Euro 2008, and another Portugal team-mate in Jose Bosingwa, who signed for the club earlier in the summer.

His exit from the Nou Camp proved to a protracted one due to the Catalans' initial valuation of around £11million for the player, despite his age.

The two-time Champions League-winner had been linked with Inter Milan, where his former Porto boss Jose Mourinho is now manager, but the Italians appear to have been put off by the price. Chelsea, however, seem to have negotiated the fee down to sign Deco on what is thought to be a two-year deal.

New coach Scolari officially starts work at Chelsea tomorrow morning and will undoubtedly be happy with the club's transfer business so far.

Deco's arrival significantly boosts a midfield talent pool already boasting the likes of Frank Lampard, Michael Ballack, Michael Essien, Mikel Jon Obi and Claude Makelele.

Yet Scolari is likely to have a busy first week ahead of him with top priority likely to be persuading England international Lampard and defender Ricardo Carvalho to stay.

Both have attracted interest from Mourinho's Inter and Lampard, with just one year remaining on his contract, recently refused to rule out a move.

Chelsea were planning to hold contract talks with Portugal international Carvalho, who has only just started his holiday due to Euro 2008, but Brazilian defender Alcides says he is returning from his loan spell at PSV Eindhoven to replace him.

Alcides has been with the Dutch club for the last 18 months and said: "PSV wanted me to stay but I have learned that Chelsea want me back. It seems Carvalho is leaving and I am going to replace him.''

Scolari's arrival at Stamford Bridge has been welcomed by former Chelsea manager Ruud Gullit.

The Dutch legend, who originally moved to Stamford Bridge as a player in 1995 before becoming player-manager a year later, is now in charge at Los Angeles Galaxy in the United States.

"He is the right choice at the moment,'' said Gullit. "I think he is a passionate coach, he does everything with the heart.

"He tries to win with good football, and he did that with the Brazilian national team and with Portugal, so he knows how to play."