I just got this from Warner Brothers a few minutes ago.  The rumors are true!!!

PARIS HILTON TO GUEST STAR ON THE CW’S “SUPERNATURAL”

(August 6, 2009 – Burbank, CA) -- Paris Hilton will guest star in the October 8th episode of The CW’s “Supernatural,” reuniting her with her “House of Wax” co-star and “Supernatural” series regular, Jared Padalecki. 
 
“Paris Hilton is playing a demonic creature that takes the form of....Paris Hilton,” said series creator and executive producer Eric Kripke in describing her role on the show.  “It'll be a fun, irreverent episode and we here at ‘Supernatural’ are thrilled that Paris agreed to do it.”
 
The episode, titled “American Idol,” will air on October 8, 2009, at 9:00 p.m. ET/PT on The CW.