Aika Mitsui is a Japanese performer primarily known as a singer and a former member of the popular J-pop group Morning Musume, but she also has a credit as a voice actor in anime. Her career as a performer began when she joined Morning Musume in December 2006 as part of the eighth generation. While active as a singer and television personality, she took on a role in the anime series Kirarin Revolution. On the November 25, 2007 episode of the variety show Haromoni@, Mitsui participated in a voice casting competition and won the role of Gurossan, a cat character, in Kirarin Revolution. The main character of the series, Kirari Tsukishima, was voiced by her fellow Morning Musume member Koharu Kusumi. This voice role appears to be her most prominent and frequently cited work as a seiyū. Outside of this anime credit, information regarding a broader career as a voice actor is not readily available, and she does not have a substantial list of other major voice roles. Her primary career remained focused on her music and performance activities with Morning Musume until her graduation from the group in May 2012.