PGP signature on social media?

I was thinking on the other day on how copycats often impersonate other celebrities via social networks deceiving the masses - it's spiraling out of control. Solution to this problem is to educate celebrities on how to use PGP signatures?

If I was a celebrity I would give my friends/fans my PGP key and use the signature to verify my identity alongside with pictures. So where do one get my public key? From the main celebrity website. Alongside with the selfie picture, name, date, and the link to their profile: they can easily verify their identity alongside with the picture including PGP signature. My only concern is that a fan can just simply copy n' paste the signature message posted on social media and post it on their fake profile - that would be problematic, no? Of course, fans would ask the celebrity to constantly create another signature message to verify their identity - kind of annoying, isn't? Maybe a selfie picture from a bathroom mirror alongside with their name, date, and link to their profile should be sufficient. Just my two cents.