The former King of Queens actress will have a recurring role in the TV Land comedy's third season.
Remini has been cast as Stuart's (David Alan Basche) fast-talking, larger-than-life sister Nicki, who visits her brother after her husband has an affair.
Nicki's arrival will cause chaos for Stuart, his roommates Phil (Donald Faison) and Haskell (Wayne Knight), and their neighbour Holly (Kristen Johnston).
Remini has landed this role in the same week that she was eliminated from ABC's Dancing with the Stars.
The actress recently revealed that she resisted competing on the dancing programme for many years because she was "living in a place of fear".
The Exes continues its third season on December 11 on TV Land.