Madonna’s daughter Lourdes, 17, starred in her high school’s production of Grease on Sunday, Dec. 8, and played the role of Betty Rizzo — and was so good that her famous mom is worried: she has a daughter who would rather sing show tunes than pop! (GASP!)

“Lourdes has caught the theatre bug. She is a very good singer and dancer, but is an excellent actress. Madonna is worried that next she will be touring in Cats rather than recording pop songs,” says a friend of the Material Girl. “Ultimately, she wants her daughter to be happy, but there is something uncool about theatre. Please, don’t say she will be replacing Carrie Underwood in The Sound of Music on TV in 5 years!”

Madonna, 55, and Lola’s father, Madonna’s ex Carlos Leon, were in attendance but kept a low profile in the auditorium.

Lourdes’ bio read: “She would like to thank her parents with all of her heart for giving her guidance and love and supporting her passions wholeheartedly.”