The well-travelled midfielder, who counts Bayern among his former clubs, has signed a short-term deal with the Brazilian outfit, albeit with the option of a one-year extension
The 37-year-old midfielder has signed a contract until the end of the year, with the option to extend for a further 12 months in December.
"Yesterday we had the joy of completing the negotiations for the arrival of Ze Roberto," Gremio president Paulo Odone told reporters at a press conference on Friday.
"He is a smart player who knows the game and his signing has the full backing of coach Vanderlei Luxemburgo and our trainers."
Ze Roberto, who was capped 84 times by the Selecao, has lined out for the likes of Real Madrid and Bayern Munich during his long career. He will return to Brazil when his current deal with Al-Gharafa expires on May 22.