Star Idina Menzel first played Shelby, Rachel’s long-lost mother on the show Glee, in episode 14 of the television series’ first season, where she appeared as a singing teacher. Shelby will return at various points throughout the show, making her last appearance in season four.
Despite her age very close to that of Lea Michele, the star was cast in the role of the mother.
Menzel, at the time of the television series, was 39 years old, while the protagonist Lea Michele was 24, which, admitted the star, had made her fearful of the next steps of her career:
“You’re afraid you won’t work anymore, and then people hire you to be someone’s mother when you should probably be their older sister. It wasn’t good for the ego.”
Menzel had previously expressed the belief that she should have played Rachel’s sister on Glee instead of her mother. Due to the 15-year age gap in real life, Shelby’s presence as Rachel’s long-lost sister could have worked as a storyline. This could have led to a different way for Rachel to find out who she is to mother her, perhaps played by an older actress than her star was at the time.
However, it’s also clear that Menzel’s portrayal of Shelby has left an important imprint on the television series, resulting in a memorable first season storyline. Despite being so close to the protagonist’s age, Idina Menzel still gave a memorable performance. However, it’s understandable that the actress doesn’t want to be cast as a mother figure for the rest of her career due to her performance on Glee.