Poser

a poser can be someone who tries to fit in faking an interest in something, usually a specific fandom or trend.

poser: Man, JoJo's Bizzarre Adventures is a great and fun anime, don't you think so?
guy: Oh bro, totally! Did you watch Battle Tendency yet?
poser: Pfft, yeah, I watched it all last night
guy: Then let's party, dude! I brought tequila~
poser: *is confused* You know I don't drink, right-?
guy: ...You're a poser, aren't you.