Watch A Cinderella Story: Once Upon a Song (2011) HD Full Movie Free on SolarMovie. Watch A Cinderella Story: Once Upon a Song (2011) online free. A modern, musical spin on the tale of Cinderella that follows a high school girl who falls for a boy...A modern, musical spin on the tale of Cinderella that follows a high school girl who falls for a boy at her Performing Arts school.