superfan       
noun [ C ] (also super-fan) uk/ˈsuːpə.fæn/ us/ˈsuːpɚ.fæn/
 超级粉丝;超粉
someone who admires and supports a person, singer, sport, team, etc. in an extremely enthusiastic way
  A wealthy superfan has bought the club. 一位有钱的超级球迷买下了这家俱乐部。 
 He turns out to be a super-fan of David Bowie.
 - More examples
 - He's a superfan of the Chicago Bears.
 - I've been to two of their concerts this year, but I wouldn't call myself a superfan.
 - The superfan makes a 500-mile trip each week to watch his favourite football team.
 - Find out whether you're a true super-fan by doing this fun quiz!