There are a lot of celebrities that use Studio Fanmail. However, there is 99.999999% chance that you will not get an authentic response. However, I have a method to using SFM. Here's How To Use My Theory:

#1.) Find a list of celebrities and their emails on SFM. There are plenty of lists posted on this site that list the SFM email addresses.

#2.) Once you've found a list and a celebrity who's autograph you want, look up other successes for that celebrity. For example, if you send Christie Brinkley a SFM email, you won't get an authentic back. However, if you send an LOR, SASE, photo, etc, you could get an authentic, personalized photo back. So don't send an SFM request to someone like this. If you could get an authentic, go for that.

#3.) If you look at some TTM and SFM successes for someone like Ben Stiller, you are most likely going to get a preprint either way (even the same picture). So, why not send an email to SFM and get the photo for free without paying for postage, SASE, ink for a photo? This is what I do.

So, here is what I'm doing: I'm sending a request to Ben Stiller through SFM, since I'll get the same TTM. However, I'm going to send an LOR, SASE, photos, to Christie Brinkley since I'll likely get a personalized and authentic signature. Of course, these aren't the only two celebrities that it'll work for: Another example would be, TTM or SFM, you'll get the same from Alan Alda.

Hopefully you can save a buck or two and still get a response/success by using my SFM Theory! Cheers and Happy Collecting!