She will play Brenda, Jeff and Audrey's new surrogate, the network said.
Rue's previous television credits include starring roles on "Happily Ever After," "Less Than Perfect," "The Big Bang Theory," "The Simple Life," "Two and a Half Men" and "Will & Grace."
The actress announced in August that she had lost 50 pounds using the Jenny Craig diet system.
Notable deaths of 2014 [PHOTOS]
Morena Baccarin to star on 'Gotham'