I realize this will come as no surprise to many, but you wouldn't believe the amount of people that were convinced that Chris Nolan had cast Hathaway as Selina Kyle only(as outlined in the official press release) and not her leather wearing alter ego. In this interview Hathway refers to herself(and indeed I believe this is the first time anyone associated with the movie has used the name) as Catwoman..
So there you go. Hathway will not simply be portraying Selina Kyle. Expect her to be suiting up and getting Batman's head all frazzled.