The character of Blair, was originally conceived as a down-home charming Texas girl. However, during her audition for the role Lisa Whelchel read several of Blair's lines sarcastically. Producers were so impressed by Whelchel's audition that they re-wrote the character to be that of a self-involved New York blue blooded socialite.
When she left after the seventh season, Charlotte Rae recommended Cloris Leachman to replace her. Rae and Leachman were classmates at Northwestern University and were roommates when they were young struggling actors in New York City.