Noun
English Wikipedia has an article on:stage motherWikipedia
stage mother (plural stage mothers)
(US) The mother of a child actor.
My dad was like a stage mother he always pushed me to do what I wanted. Jim Carrey
Terri and her mother arrived. She was obviously a dedicated stage mother because she was loaded down with camera equipment, looking like a Japanese tourist. Audrey Meadows
My mother was the worst kind of stage mother. She would make me and my younger sister and brother little duckling costumes and put us in kiddie shows. Renee Fleming