Im gonna be in a summer play at my church! i have to sing in front of everyone!!! HELP!!!!!!!!!!!!!!!!!!!!!!!!

im going to be in a new play at my church next week and i have to sing in front of a bunch of people. i have a good part and i still want to go on with the play but im too scared to be singing in front of people who i don't know. im not even comfortable singing in front of my family members. what should i do??! PLZ HLP!!