Is it OK for me to sing on stage with my overweight 9 y/o daughter at the talent show?

My daughter, after seeing Hannah Montana, is convinced that she wants to be a famous performer. The talent show at her school is coming up in a few weeks, and she was one of the few people who signed up for it so she was accepted. I am concerned that if she gets on that stage, she will make a fool of herself, being quite a horrible singer. Being overweight, she has low self-esteem and I do not want the other children to have another reason to ridicule her. I am considering trying to sing on stage with her for moral support, but there is one problem. Her act requires a ballet tutu and pointe shoes for all members, and I worried about what the other teachers and parents would think of me if I took part in such a thing. Any help or advice would be appreciated, and thank you in advance for all your help.