She wasn't alone there, in fact the whole star wars including Darth Wader himself were there. It would be hard for one to say Sara Jean Underwood doesn't go all out for her part in G4's Attack of the Show. This is just one more example in a long line of examples but I don't think she's just doing it for the job.
This is a woman who really has fun with her work. She it requires her to be a bit sexy at times but a lot of people in the entertainment industry experience that. She not only doesn't seem to have a problem with turning on the sex appeal every now and again but actually seems to enjoy it. One of my favorite things about watching Sarah is the joy she has for what she does. Nothing sexier than that.