Holly Madison hosted “HollyWeen” at Studio 54 nightclub at MGM Grand, donning a gorgeous Queen of Hearts costume. She walked the red carpet and told reporters that she chose her outfit in hopes of having a Vegas-inspired ensemble.

Photo Credit: Erik Kabik/RETNA/erikkabik.com

Tabú Ultra Lounge at MGM Grand welcomed 90210’s AnnaLynne McCord as she hosted her little sister Rachel’s 21st birthday with a night of haunted seduction. The young starlet arrived at the Las Vegas hot spot with both her sisters Angel and Rachel McCord. AnnaLynne choose to dress up as a seductive catwoman.

Photo Credit: Erik Kabik/RETNA/erikkabik.com

Kellan Lutz and Ashley Greene of Twilight celebrated at TAO in the Venetian.  They are used to being dressed as Vampires for the new movie, “New Moon,” which comes out on November 20th, but for Halloween they dressed up a little different.

Sam Trammell and Rutina Wesley (who is a Las Vegas native) from True Blood partied at LAVO.   The four actors posed together for a group shot!

Photo Credit: Denise Truscello/Wireimage