The actress is to reprise her role as Jack Donaghy (Alec Baldwin)'s former flame Elisa in the January 31 instalment, according to Entertainment Weekly.
30 Rock's series finale will also feature the return of Julianne Moore as another of Jack's great loves, Nancy Donovan.
Law & Order: SVU star Ice-T is slated to cameo in the episode as well, as is US House Minority Leader Nancy Pelosi.
30 Rock wrapped production just before Christmas with a special party that gathered the cast for one final group photo.
The series has won ten Primetime Emmy Awards and six Golden Globes throughout its six-year run.
Watch a clip from 30 Rock below: