Alberto Aquilani has passed a medical and signed for Sporting CP in Lisbon.
The 31-year-old midfielder was a free agent after his contract with Fiorentina was not renewed.
Aquilani passed a medical with Sporting CP in Lisbon and the club announced his arrival on Thursday evening.
The club went for the Italian after failing to secure Kevin Prince Boateng.
It is reportedly a three-year contract worth €2m per season.
Aquilani had been considering Sampdoria and a move to Major League Soccer in America.
He grew up in the Roma youth academy and was sold to Liverpool for €20m in 2009, but injuries meant he never really made his mark.
Loan spells followed at Juventus and Milan, then he moved to Fiorentina in 2012.