MILAN (Reuters) - Ronaldinho has promised to work hard at new club AC Milan after leaving Barcelona under a cloud.

The Brazilian forward, who suffered form and fitness problems at the Nou Camp last term, will land in Milan later on Wednesday and undergo a medical before signing a deal until June 2011. He is then expected to be presented to the media.

His transfer has taken three months of bargaining and will initially cost 21 million euros (16.7 million pounds), much less than Premier League side Manchester City were reported to have bid.

"I am sorry for the wait but the facts show that I have always wanted Milan," Ronaldinho told Gazzetta dello Sport.

"This is not the moment to talk about Barcelona because I want to enjoy this new chapter of my life. I will only say that at Milan I promise commitment, not only on my technique."

Ronaldinho caused a row at Barcelona even in his last few days at the club when he was told he would not be able to represent Brazil at the Olympics.

Milan have blocked compatriot Kaka from attending but media reports on Wednesday said part of Ronaldinho's deal with the Rossoneri was to allow him to go to Beijing next month.

Beating off English side City to sign the 28-year-old is being seen as a coup in Italy given that Serie A has slipped behind the Spanish and English leagues in recent seasons.

Money is also tighter than usual at the San Siro this season with Carlo Ancelotti's side only in the UEFA Cup, so no further signings are expected. Arsenal's Mathieu Flamini is the other major arrival.

(Reporting by Mark Meadows, editing by )