The 32-year-old will make the move after two years at English Premier League champions Chelsea, where he failed to make the expected impact due to injury and poor form.
"After intense negotiations, the player, who took part at two World Cups, has been released by the English club and will sign a two-year contract," 'Flu' said on their website.
The club added that the former Porto and Barcelona player would be officially presented on Monday.
Deco, full name Anderson Luis de Souza, was born near Sao Paulo and began his career with Corinthians where he barely made an impression before leaving to join Benfica in 1997.
He made his name after joining Porto two years later and was given Portuguese nationality in 2002.
Amid great controversy, he was picked by Portugal coach, and fellow Brazilian, Luiz Felipe Scolari the following year. He made his debut in a friendly against Brazil and celebrated by scoring the winner as Portugal won 2-1.
Deco played in two World Cups for Portugal - 2006 and 2010 - and two European championships helping them reach the final on home soil in 2004.
He won the Champions League with Porto in 2004 and then again with Barcelona two seasons later.
Brazilian players often return to finish their careers at home, but the fact that Deco has played for another country makes his case more unusual.
