My friend is obsessed, help...?

i had a crush on a popstar when i was younger,i had pictures all over my bedroom wall and everything to do with him.Your friend is just going through a phase in her life and will grow out of it in her own time.If it is anoying you that she is talking about it all the time then just say to her that you love being her friend but you don't want your entire coversations to revolve around a person that is not even in your group of friends.Tell her that there is more than one topic to talk about,but don't let this phase ruin a good friendship.