Hi,i'm looking for a shounen ai manga where a guy has a classmate who looks very simple bu...

Hi,i'm looking for a shounen ai manga where a guy has a classmate who looks very simple but then the guy sees him again,but this time the simple looking classmate is dressed like a girl.The guy sees him again and asks him questions which attracted attention as they were in a crowded place.I can't remember it well and want to read it again so please tell me if you know the name of this manga.