Written by Ayase and based on Aka Akasaka's short story '45510', 'Idol' is a pop track with hip-hop elements, depicting the two-faced nature of a star in the Japanese idol industry, as well as perspectives on the anime's character Ai Hoshino from her fans, her B-Komachi's bandmates, and herself. The song was released on April 12, 2023, through Sony Music Entertainment Japan, served as the opening theme of the Japanese anime series Oshi no Ko. ' Idol' ( アイドル, Aidoru) is a song by Japanese duo Yoasobi from their third extended play, The Book 3 (2023).