Mitsui Aika (光井愛佳)
- Nicknames: Mittsii (みっつぃー), Aika (あいか)
- Birthdate: January 12, 1993
- Birthplace: Shiga, Japan
- Blood Type: O
- Height: 156.4 cm
- Favorite food: Plums, strawberries, roast beef, kombu, cuttlefish
- Disliked Food: Chocolate
- Talent: Bowling
- Skills: Massage, keeping her room tidy, camera photoshots
- Hobbies: Shopping, looking through brochures, talking to herself, taking pictures, making sushi.
- Motto: Hakuna matata
- Favorite words: Unbeatable in heaven and earth
- Favorite colors: Black, purple, gold
Joining as a member of the eighth generation from the audition in Japan during December 2006. Mitsui’s audition process was documented during the late 2006 episodes of Hello! Morning. She performed Ayumi Hamasaki’s “Blue Bird” in round one of her audition and Morning Musume’s “Furusato” and “Osaka Koi no Uta” in rounds two and three.
Her first appearance at a non-Hello! Project related event took place on February 8, 2007, on Utaban, as part of Morning Musume.
In October 2007, Mitsui was placed in the unit Athena & Robikerottsu along with fellow Morning Musume member Niigaki Risa, as well as Nakajima Saki and Okai Chisato of °C-ute.
On the November 25, 2007 episode of Haromoni@, Mitsui got the seiyuu role of Gurossan in the anime Kirarin Revolution starring Kirari Tsukishima, voiced by Kusumi Koharu.
On April 6, 2008, Hello! Project announced that that Mitsui would not be able to perform in the 2008 spring tour due to her being in very poor health. Later in the week, it was discovered that she had suffered from acute appendicitis, and would be out of action for two more weeks.
It was revealed on July 2009 that Mitsui Aika would form part of Tanpopo # along with Kamei Eri, Yurina Kumai and Okai Chisato.
In 2009, it was announced that Morning Musume will be attending the annual anime convention, the Anime Expo in Los Angeles, California as Guests of Honor in July. All members of the current lineup including Mitsui Aika attended the event. Morning Musume held autograph sessions and a concert. The number of fans that attended the concert reached over 7,000 people.
Mitsui currently has a blog only available to Official MM Fanclub members called “Pastel Colour Days”.
In December 2010, Mitsui was announced her first Photobook titled ‘Mittsi.’ Mitsui mentioned had mentioned in several interviews before that she had wanted a photobook, and was very happy at the announcement.
On May 9, 2011 she suffered a left ankle bone fracture and she was advised to rest for 8 weeks, after which she was again advised to rest for 8 weeks, resulting in her missing out on the rest of the Hello! Project Summer 2011 Concert Tour.
- She has a habit of speaking to herself
- Morning Musume Happy 8ki Audition songs:
- Round 1: “BLUE BIRD” (Hamasaki Ayumi)
- Round 2: “Furusato” (Morning Musume)
- Round 3: “Osaka Koi no Uta” (Morning Musume)
- She became good friends with Yoshizawa Hitomi, who adopted an “older sister” figure
- Proclaimed herself to be Kusumi Koharu’s new rival
- Youngest member of Morning Musume
- Her favorite number is 397 because it was her entry number in the audition. Her mother stated she won because it means bloom like a flower (sa ku na = 397)
- Has a toy poodle named Leo
- Lives with her older sister in Tokyo
- Her grandmother named her
- Has an inhaler with her in concerts in case her breathing gets bad
- In the period between the graduation of Linlin and the addition of the Ninth Generation, she was the only member of the group who was under 20 years old.
- Morning Musume (2006 – )
- Athena & Robikerottsu (2007 – 2008)
- Tanpopo # (2009 – )
- Guardians 4 (2009 -)