be a prima donna

Prima donna means "first lady" in Italian.

1. To be the lead female singer in an opera company. With her voice, I'm sure that Shirley will be the opera company's prima donna. I've always wanted to be a prima donna, ever since I started singing as a little girl. I know I don't have the best voice, but that's OK—I'm fine with being in the chorus. I don't need to be the prima donna.

2. To be very demanding and temperamental. Kathleen is such a prima donna—there's just no pleasing her. Now that you're a star, don't be a prima donna, running all the assistants on set ragged. I know I'm the boss now, but we're still all on the same team—I'm not going to be a prima donna all of a sudden.