Hello! I need help finding a BL manga!

First off, it's student x teacher.
This teacher is an Otaku and stans an idol group and would buy their merchandise and go to their concerts, in one event he requested to hug his bias.
He compliments this leader because he sees that he tries hard for the group, even tho he's not the best at singing, nor dancing.
One day, during class attendance, a student who rarely comes to class attended, because it's an exam week, as he was marking attendance he recognizes his face, the teacher then was stunned because he looked exactly like this idol, and has a similar name to the attendance as his stage name.
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I remember reading this and I can't remember the title and I tried looking for it but no luck, please help!!