Miyuu Sawai (沢井美優), born October 23, 1987, in Kanagawa, Japan, is an actress and idol who played Usagi Tsukino/Sailor Moon/Princess Serenity/Princess Sailor Moon/"Sailor Rabbit" and Queen Serenity in Pretty Guardian Sailor Moon.
A former model in the junior fashion magazine LOVE BERRY (with Chieco Kawabe), she debuted in the teen TV drama Kids War before PGSM, and has since released several idol DVDs, appeared as the main character of Chain - Rensa Jusatsu, and had a cameo in Booth. She also voiced Noah in Fullmetal Alchemist: The Movie - Conqueror of Shambala, and had a small role in Black Cat.
In the original PGSM casting, she was not selected. However, upon the insistance of Naoko Takeuchi, she was finally cast as Usagi Tsukino, and is now considered by many fans as very appropriate for the role due to her similar personality.
More recently, she played the main supporting role in a children's stage drama during the summers of 2006 and 2007, in which Moeco Matsushita had the starring role. She also starred in a prime-time historical drama in the summer of 2007.
 Personal Trivia
- It has been rumored that she is the younger sister of Emi Hasegawa due to some circumstantial clues, but this has been neither proven nor officially acknowledged by the two artists.
- She is a qualified scuba diver.