Barcelona forward Ronaldinho will sign for AC Milan on Wednesday in a deal that is worth €21 million, possibly rising to €25millon.
'AC Milan and Barcelona have reached an agreement in principle over the transfer of Ronaldinho,' the Italian club said in a statement.
'The player will be in Milan tomorrow to undergo a medical and sign a contract that will keep him at Milan until June 30 2011.'
Milan will hope the medical passes without a hitch as they are thought to be determined to unveil Ronaldinho on the same day their squad begins pre-season training.
Reports in the Italian media claim the Brazilian international's brother, and agent, Roberto de Assis has agreed a €6.5million contract with the Rossoneri to match what Ronaldinho currently earns in Catalonia.
The Serie A side, who finished fifth last season and will be in the UEFA Cup this term, beat off competition from English Premier League club Manchester City for the 28-year-old.
Ronaldinho spent five years at the Nou Camp, helping Barca win the Champions League in 2006 and their domestic title in 2005 and 2006.
The Brazilian playmaker was named FIFA World Player of the Year in 2004 and 2005 but has been allowed to leave Barcelona after suffering form and fitness problems last season.
Ronaldinho's capture would put an end to Arsenal striker Emmanuel Adebayor's hopes of moving to Milan. Galliani has previously stated that only Adebayor or Ronaldinho would end up at San Siro.
Coincidentally, Adebayor has now been linked with Barca in the media.
Although Milan are thought to have offered only €21 million, much less than the €32 million Premier League side Manchester City were reported to have bid, Ronaldinho's wish to go to Milan rather Manchester was the deciding factor.
Barca sports director Txiki Begiristain said: 'The principle of agreement finally established a transfer fee of €21 million, plus four million more in the form of performance-related bonuses depending on AC Milan's qualification, in future years, for the Champions League.
'This agreement in principle was reached thanks to the player renouncing his right to 15% of the fee.'
Galliani, who has chased the Brazilian for three months on and off, flew to Barcelona at the start of the week and has been in talks with Barca and the player for the past two days.
Ronaldinho could walk into an immediate row at Milan given his wish to represent Brazil at next month's Beijing Olympics.
Barca had refused to release him for the Games and Milan could make the same decision having already stopped compatriot Kaka from going to China.
Ronaldinho will join Mathieu Flamini, Gianluca Zambrotta, Marco Borriello, Christian Abbiati and Luca Antonini as new faces at Milan this season.
Coach Carlo Ancelotti has said he wants to play Ronaldinho alongside Kaka in a Christmas tree formation behind a striker.