Ronaldinho was given a welcome even bigger than Brazil great Zico when he was officially unveiled as Flamengo's new signing to a samba beat on Wednesday.

More than 20,000 fans, entertained by singers and dancers while they waited, swarmed the Flamengo headquarters to greet the gifted, party-loving forward with the toothy grin who was transferred from AC Milan this week.

Not even that number greeted Flamengo idol Zico on his return to Rio from Italy in 1985.

Ronaldinho, a World Cup winner with Brazil in 2002, looked overwhelmed by his reception at first but promised the Flamengo faithful titles in return and told them his goal was to help his country win a sixth world crown.

"That's my objective. I decided to return to Brazil for that. Many come back to Brazil only to close out their careers," Ronaldinho, decked in the club's red and black colours, said as he spoke to reporters for the first time as a Flamengo player.

"After years away from Brazil, the World Cup and the (2012 London) Olympics have given me motivation to return," added the 30-year-old, overlooked by his country for the 2010 finals in South Africa.

The former FIFA World Player of the Year, who hit a peak for Barcelona when he inspired them to the European Champions League title in 2006, signed a four-year contract with Flamengo.

"I want to take the name of Flamengo as high as possible, winning as many titles as possible and repaying these fans' love... I want to give the fans happiness," he said.

Joyful football was Ronaldinho's trademark during his peak years in Europe but he had struggled for a first team place at Milan who gave him permission last week to seek a move to a Brazilian side.

"It was a marvelous feeling... I didn't expect such a big party," Ronaldinho said.

"I'm proud to have got such a reception and to be compared with Zico. This number 10 shirt has a history and I always thought of playing for a team with fans like this."

Ronaldinho will make his debut for Flamengo during the Carioca (Rio de Janeiro) state championship starting later this month.