Hello,

I'd just like to mention that there are a lot of fake accounts on social media too. People who make their profiles look just like the celebrity's that they're impersonating. They'll see that you follow the celebrity and then the fake one follows you back for whatever dodgy reason they have up their sleeve. It's my guess this impersonators account may have been reported and then removed, and so it appeared they unfollowed you. Or if it hasn't been removed, go and check to see if it's an authentic account. I doubt it is.