Ronaldinho has expressed his delight at finally completing his move from Barcelona to Milan.
The 28-year-old played down reports that his lifestyle in Spain had compromised his fitness.
“I have always lived a regular life and I will continue like that. I am in good physical condition,” he said.
“Every player dreams of playing for Milan. It is a special emotion and I hope to bring happiness to the fans.”
Thousands of fans turned up at the stadium to welcome Ronaldinho to the club, with the San Siro nearly half full.
“I already feel at home here,” he added, speaking in Portuguese.
“It was a beautiful period (at Barcelona), we won important trophies but after recent disappointments we decided together to go our separate ways.
“Here I can go back to being happy and to reaching new personal and team objectives.”
Ronaldinho said he was particularly looking forward to playing alongside his Brazil team-mate Kaka at Milan.
“It will be exciting to play with Kaka. He is among the best in the world. He is also a friend and we play well together,” he said.