To me, it looks like it is probably real. I'm assuming you got it recently through her film set, which is the only place that I have seen her sign authentically TTM. However, she has sent secretarials from film sets before, but judging from the style of her signature, I'm inclined to say it is authentic. Her IP's are of only a little help to determine authenticity because she often only gives an "E" or so. I've compared it to the old TTM's from the set of Hitch and they seem to match for the most part. The only difference I really see is that the M is not connected to the "endes" in the older signatures, but the writing style is very much the same. Since that was so many years ago, I am willing to concede that her signature changed slightly over time and that this is indeed authentic.
Sorry I just saw other successes with the same sig. This is unfortunately an autopen. Also, the other scans had the little pools of ink at the end of the signature that is sometimes seen in autopens, but your scan is too hard to tell if those are there. Didn't know she used them until now.
Autopenned. Sorry about that. :/
Congrats on getting a success, anyways!
http://www.freewebs.com/xolindsey87/ Recently Sent Out: Taylor Lautner VV, Nick Jonas VV Favorite Success: the Jonas Brothers, Taylor Swift x4, David Archuleta x3, & Jason Ritter Q&A! (: Recent Successes: Monique Coleman VV