Real Madrid have completed the signing of Brazilian playmaker Kaka from AC Milan on a six-year deal.
The fee is reported to be about £56m, which would be a new world record in pounds sterling, surpassing the £45.6m Real paid for Zinedine Zidane in 2001.
Kaka, 27, revealed he has joined the Spanish club to help the Italians overcome their financial difficulties.
"I wanted to stay but the world crisis affected my decision," he said. "I knew I'd only leave Milan to play for Real."
The attacking midfielder, speaking after having a medical in Recife, where Brazil face Paraguay in a World Cup qualifier on Wednesday, added: "I spoke with the Milan directors and we reached the conclusion that the best thing for everybody would be to sell."
And he revealed that the deal had been in the pipeline for some time.
"I've been weighing up the offer from Real Madrid a lot," he confirmed.
"It's an important project for me to continue growing in my career. I'm not going to Real Madrid for money, as I had other offers.
"But the deal was sealed a long time ago. I wanted this move to be announced sooner. For me, it's a relief that it has been announced now."
And that deal was sealed by the ambition of returning Real president Florentino Perez, who previously led the Spanish club from 2000 to 2006 - during the famous galacticos era.
"The president is already making contact with potential signings and is putting together a competitive team, one which will try to once again become champions in Spain and Europe," continued Kaka.
"That's why I chose Madrid. They have historic players there already, such as Raul and Iker Casillas.
"It will be an important challenge for me. We're going to win many titles again."
Kaka had the opportunity to join Manchester City earlier in the year during the January transfer window for a reported £100m but opted to stay in Italy.
"Manchester City and Real Madrid are two different clubs with different situations," he explained.
"At that time, it was mid-season, I had a strong emotional impact due to the Italian fans requesting me to stay and I decided to stay.
"Now another chance came up and AC Milan is in a big crisis [financially]. For me, the sporting project at Madrid is interesting and will be an important boost to continue my career at the highest level."
Kaka had been at Milan since moving from Brazilian side Sao Paolo in 2003 for 8.5m euros and he leaves the Rossoneri on good terms.
Becks helped me choose Real - Kaka
"I want to thank Milan, as they were the club who put me on the international scene. They gave me the opportunity to become a big name in Europe," he stated.
"I'm happy to leave Milan by the front door, with a lot of friends. It has been very emotional to see what the Milan fans have done for me."
A short statement on the Real site said: "He is a Real Madrid player now after an agreement was reached with AC Milan.
"The Brazilian has passed all the tests of the medical examination satisfactorily. Kaka has signed a contract with Real Madrid for the next six seasons."
A Milan statement read: "It will be very difficult to fill the void that will be left by Kaka.
"We offer him the most cordial and affectionate wishes for the continuation of his sporting career.
"He is a shining example of professionalism and commitment.
"AC Milan thank the man and the great champion Kaka for his decisive contribution to the many victories achieved in the six years of his commitment."
The official unveiling in Madrid is unlikely to take place until the end of the month because Kaka is in the Brazil squad for the Confederations Cup in South Africa, which starts on Sunday.
BBC Sport's South America correspondent Tim Vickery added: "He has been signed because of what he can produce on the field and for the dressing room influence he will have on this new pack of galacticos."
Kaka has long been a target for Real Madrid since former president Ramon Calderon promised to sign him in his election campaign in 2006 but failed to deliver.
He is the first capture for the returning Real president Perez, who spent large fees to bring the likes of Ronaldo (£23.2m), David Beckham (£24.5m), Luis Figo (£37m) and Zidane to the club.
The likes of Manchester United's Cristiano Ronaldo, Liverpool's Xabi Alonso, Valencia's David Villa and Bayern Munich's Franck Ribery have been linked to Real since Perez's unopposed election signalled the return of their vast spending.
Zidane joined Real from Juventus for a fee reported to be 73m euros in 2001.
Kaka's fee is thought to be about 65m euros but with the fluctuation in exchange rates his fee represents the most paid in British terms.
Perez's comeback is on the back of a pledge to relaunch another Galacticos era, with Kaka one of his chief targets.
Archive - Kaka scores against Croatia
The Brazilian enjoyed great success in his six years at the San Siro.
In 2007 alone Milan picked up the Champions League as well as the Uefa Super Cup and the Fifa Club World Cup, while his Brazil side won the Confederations Cup and he was also voted the Fifa World Player Of The Year.
He has also won the Seria A title and was part of Brazil's 2002 World Cup-winning squad.
Although under contract at the San Siro until 2013, in January Manchester City made an audacious £100m bid, offering a reported £500,000 a week in wages but Kaka opted to stay in Italy.
More recently he was linked with a move to Stamford Bridge following the arrival of former Milan boss Carlo Ancelotti at Stamford Bridge.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.