Research it. or put the movie link (from imdb, thats what i do) and see if anyone knows anything about the movie in Add/Request a Via Venue Address

Hi I was wondering how to find out addresses for actors etc... when they are shooting movies. I am under the impression that some movie stars are best to sign authentic vv. So I was wondering how to find that out, because it seems like many of the ones I want to send are either fakes or don't really sign. I don't really see any new venues and am wondering if I should go that route still or try their normal addresses and hope for the best. Any help would be nice.
Thanks,