The veteran revealed his desperation to pull on a Fluminense shirt for the first time after completing his move to the club.
Ronaldinho says his legs are "trembling with desire" to play football after joining Fluminense on a free transfer.
The 35-year-old left Mexican side Queretaro earlier this summer after spending last season with the club, but still retains the drive to play on.
"It's good to return for a big club," he said. "I'm very happy and motivated. I wanted to play after seeing the stadium (Maracana) and the fans with all their support.