Right show, wrong actress. Before Markie Post joined the cast, the role of the sassy blond public defender was played by Ellen Foley, who was the female singer in 'Paradise by the Dashboard Light'.
Ellen Foley (born 1951, St. Louis, Missouri) is an American singer and actress whose range of talent and experience has spanned edgy rock, mainstream pop, standard Broadway, sitcom television, and Hollywood. She has released three albums on her own, but she is best known for her collaborative work with Meat Loaf.
Her first big break was singing the duet with Meat Loaf on 'Paradise by the Dashboard Light' from the 1977 album Bat out of Hell. Although Karla DeVito is featured on the video, she is miming to Foley's vocals.
Her best known television acting role is the role of Billie Young on Night Court for one season, after which she was replaced by Markie Post. She had small but memorable parts in Miloš Forman's 1979 film adaptation of the stage musical Hair, as well as the films Cocktail, Fatal Attraction and Married to the Mob.
http://en.wikipedia.org/wiki/Ellen_Foley
[Added text and reference link - McG]