It's the one day of the year when they can be anything but their famous selves. Lindsay Lohan can channel Sarah Palin. Paris Hilton can play cop. Britney Spears can be ... a hot pink cat.
But for some, of course, no amount of face paint or dressing-up can hide that they're bona fide celebrities. That's not going to stop Hollywood from celebrating Halloween. Below, check out how some stars plan to spend the holiday, and how they partied in years past: