Majo Kaitou LIP☆S

Miku Hoshino is a just a regular girl who thinks of nothing but her favorite idol, Rei, from the totally popular group M.A.G. When her school duties make her miss the concert she was desperately hoping to go for, she does what any girl would do—takes the help of a witch! But when the witch turns Miku into a witch, too, her life becomes anything from ordinary...and a certain keen-eyed detective seems determined to keep it that way!

(Source: Kodansha Comics USA)