Hailing from Gainesville, Georgia, Lynne is the middle child of three to Nat Ashe, a poultry industry executive, and Bebe Ashe, a part-time legal secretary. Lynne knew by the age of four that she wanted to be both an actor and a writer.

Around age 8, she was distressed to learn that the stage name she had picked for herself was already taken. It was Debbie Reynolds. Lynne is primarily of Irish and English descent, with rumors that she is very distantly linked to Thomas Ashe, one of the first settlers in Ireland in the 1500s, who in turn is very distantly related to Queen Elizabeth II.