Masumi Itō (伊藤真澄, born May 21) is a vocalist, composer, and musician from Ibaraki Prefecture, Japan. As a composer she is often credited as Hikaru Nanase (七瀬光) and occasionally Heart of Air. She began playing the piano when she was six years old. She debuted in 1993 with her album Harmonies of heaven. Her most notable early work was the soundtrack of Gemfire, the American version of Super Royal Blood, a popular Japanese title of the time. As of 2015 she has created over 1000 individual compositions and the soundtracks for over 35 animated series and video games (including Galaxy Angel, Zone of the Enders, Gravion, Da Capo, Scarlet Fragments, Pita-ten, and Infinite Stratos) and sung theme songs for a number of others (Azumanga Daioh, Haibane Renmei, Sister Princess).

In addition to her solo work, she is/was a member of many musical units including Oranges & Lemons (with 上野洋子), Mariaria (マリアリア, with さねよしいさ子), IKIRU (イキル), SYNERGY SYSTEM, midori, and AQUA VOCE.