Gilberto heading home to join Gremio
The 34-year-old midfielder will leave Panathinaikos at the end of the season and join the team from the southern Brazilian city of Porto Alegre next week in an 18-month deal.
"We are very happy with this signing. Our commitment is to strengthen further our squad so Gremio will have a great campaign in the Brazilian championship," club president Paulo Odon said in a statement on their website.
Gilberto Silva, who began his career at Atletico Mineiro, helped Brazil win their record fifth World Cup in 2002 before signing for English Premier League club Arsenal.
He was also in Brazil's squad at the 2006 and 2010 World Cups, where they were eliminated in the quarter-finals, and captained his country to victory in the 2007 Copa America in Venezuela.
Gilberto Silva follows other top Brazilian players returning home since Ronaldo began the trend in 2009, including Adriano, Ronaldinho, Rivaldo, Elano and Luis Fabiano among others.