A friend of mine has a completely unscientific, observing-from-afar theory about Jennifer Aniston.

It goes like this: To look as good as Aniston does, but to go through as many high-profile men as she does without one of them hanging on to her for dear life must mean she truly is a high-maintenance nut-job.

We couldn't help but think of our friend's theory while watching Aniston's guest-appearance on 30 Rock, which airs tonight on Citytv and NBC. To put it simply, Aniston's character is a bang-on representation of what my friend thinks Aniston must be like in real life.

Aniston plays Claire Harper, who is an old college roommate of Liz (Tina Fey) and Jenna (Jane Krakowski). Claire shows up for a visit in New York, which instantly makes Liz and Jenna apprehensive, since Claire is, well, kind of wild and literally crazy, and still behaves like a promiscuous student with no responsibilities.

"(Claire) is like a human Macarena -- something everyone did at parties in 1996," Liz says.

Of course, as Claire gets off the elevator, she runs into Jack (Alec Baldwin), who instantly notices Claire's hot factor. Subsequently, Jack gets to find out first-hand just how crazy Claire is.

We have to say, Aniston, 39, looks absolutely great in her 30 Rock appearance. There's one scene where she has her legs up on the desk in Liz's office that surely will stick with us for a while (Jack is equally agog, by the way).

Aniston has been in the news this week because of her interview in the December issue of Vogue. Aniston, the former Mrs. Brad Pitt, says Angelina Jolie, the current Mrs. Brad Pitt, was out of line when she spilled details about her steamy relationship with Pitt while they were filming Mr. & Mrs. Smith. Of course, Pitt still was married to Aniston at the time.

So, is Aniston really nuts? Or is there something to the old cliche that goes, "When everyone really is out to get you, paranoia is just good thinking."

Well, we'll know for sure if, at the last minute, Aniston gets replaced by Jolie on 30 Rock tonight.