Could you tell me if there is a psychological personality disorder with these people I will discribe...?

There is this couple in my social circle ( they act like bf/gf but nothing confirms this on their relationship status on fb) She is much younger then he, he is out of grad school but still living at home she is only 18/19 and looks like a celeb look alike who plays the guitar. The celeb she looks like, they are both big fans and they both idolize this celeb; the girl speaks about the celeb so much and how great she is, so wonderful, talented, pretty, she looked hot (almost like she is trying to pump herself up) he has younger girl dress up like the celeb for a costume party(which she has done before) but he also makes reference about her looking like her and also has this girl fix her hair like her when they go out. What I have seen and others too, its like the real celeb is like the fantasy in the relationship, and he/she seems to believe this young girl he is dating is the real celeb and she is so over confident I think she thinks she is. They both seem to feed off this and go to parties playing their guitar. It seems really weird to a lot of people, I do know this guy diff has a bit of a Narcissistic personality but what would you call this trio relationship with the invisible posed celeb.... its really weird.. Thanks for your input.