Oshi to no Riakoi Jirai desu

Tenma, who is recognized by everyone as a perfectly handsome man, proposes to Amane, a member of his fan club, on a date, but is rejected.
The reason is "because he's my oshi." Huh? Doesn't "oshi" mean "to like" something?
Unable to accept this, Tenma devises a plan (a charade) to get Amane to notice him.