Itou Masumi, born May 21 in Ibaraki Prefecture, Japan, is a singer-songwriter and composer. Itou has composed the soundtracks to many anime television shows, and is part of the bands, Oranges & Lemons and Heart of Air.
She graduated from Musashino College of Music. Her husband is music producer Itou Yoshiyuki.
She also goes by the pseudonym Nanase Hikaru.