Pam's Vanishing Trick Exposed

Pam's going to play a magician's assistant for Hans Klok at Planet Hollywood in Vegas. They usually disappear with a poof, but Pam made a very visible exit from Winston's last night, bombarded by photogs as she attempting to sneak out the back door while hiding behind a friend's jacket.

Pam's sometimes party-pal, Paris Hilton, was less resistant to the flashing paps -- one of whom apparently brought a searchlight to brighten up the back of Hyde. The club was also home to Hilton's ex, Stavros Niarchos, and Jack Osbourne -- who told TMZ cameras that nothing interesting would happen while waiting for his car ... guess he didn't see this video of his sister.

Also out: Tonight's "American Idol" mentors, Bon Jovi, "Battlestar Galactica" hottie Tricia Helfer and "Showgirls" actress Rena Riffel with an unfortunately wigged out Mary Carey.