Harper will play Claire, the sister of Sophie (played by Lesley Ann Warren) and aunt to Susan (played by Teri Hatcher).
Harper recently starred on Broadway in the biodrama Looped last season and received a Tony Award nomination for her portrayal of Tallulah Bankhead. Among her other Broadway credits are The Tale of the Allergist's Wife, Subways Are For Sleeping and Wildcat. In addition, she starred in the national tour of Golda's Balcony.
She is best known for her portrayal of Rhoda Morgenstern on television's The Mary Tyler Moore Show and Rhoda.