Momoko Yachigusa is a teacher at Four Star Academy and serves as the instructor of the Bird Theatre Class. She has a calm and composed demeanor, often using comparisons to illustrate her points, and she holds a deep passion for serious acting. This passion is the driving force behind her teaching, as she guides her students in the theatrical arts. In terms of appearance, she is a fair-skinned woman with slanted green eyes and lavender eye shadow, and she has long indigo hair that features powder-blue streaks in her bangs. Her role in the story is primarily that of a mentor, providing guidance to the students in the Bird Theatre Class and supporting their development as idols and actresses. While she maintains a composed exterior, her enthusiasm for her craft is evident in the way she instructs and motivates her students. She reappears in the later series Aikatsu on Parade!, continuing her role as the Bird Theatre Class teacher. Her notable abilities include her expertise in theatre and her ability to nurture the talents of the idols under her care.