CLASSMATE NO MOTO IDOL GA, TONIKAKU KYODOU FUSHIN NAN DESU.

Saegusa, who retired from idolry when she went to high school, is good-looking and intelligent. She is always cheerful and friendly, and is the most popular person at school. Takuya, however, knows a certain side of the highbrow Miss Saegusa. Today, too, a suspicious-looking woman in a dubious disguise appears at the convenience store where he works part-time. She is, in all likelihood, that Saegusa-san...? — Description from AniList community (anilist.co).