At one point a character describes Hoshino's mom as looking like Izumi Inamori. This is the actress that plays Hoshino's mom.
Ayumi Ito spent weeks training on the piano in order to do all of her scenes without a double. She became so obsessed with Debussy's "Arabesque No. 1" that she made it her cell phone ring tone.
Lily Chou-Chou is a fictional singer. The songs in the movie are sang by a Japanese singer named Salyu.
Ayumi Ito really shaved her hair for the movie.