Thank you so much for your help!

I usually address them by their full name or whatever their name is in the media.

I don't think there is a proper way. If I'm writing to Dave Grohl, I'd just write: "Dear Dave", but if they're Sir/Dame I'd write "Dear Sir/Dame_______,"

Please forgive me if this has already been discussed. I was wondering, when you guys write letters to celebrities, how do you typically address the individual? Like, if you were going to write to Frank Sinatra (I'll use him as a general example since he's no longer with us), would you generally say "Dear Frank," "Dear Mr. Sinatra," or something else altogether? Are there general rules of etiquette about this?

Thanks in advance!