Star vs. the Forces of Evil - Season 2 Episode 40 -

The songstrell Ruberiot is ordered to write a song about Star for the tradition of Song Day, but Star is reluctant to participate because it portrays princesses as being perfect. Ruberiot ultimately convinces her to let him write a song about the real her, but inadvertently reveals to the people of Mewni that Star lost the book of spells, and that she has a crush on Marco.