also: ファン・クラブ
An organized group for fans of a celebrity, sports team, or media franchise.
彼女はアイドルのファンクラブに入っている。
She belongs to an idol's fan club.
A fan-club-members-only event was held.
She joined that idol's fan club.
I started a fan club for my favorite band together with friends.
You can enroll in the fan club through the official website.