Hollywood Goes Trick-Or-Treating!

Heidi Klum bared her kitty claws as she arrived at her 8th annual Halloween party-sponsored by Captain Morgan-at Hollywood hot spot the Green Door in Los Angeles.

"I wanna know if y'all can shake your tambourine!" said a devilish Eve before launching into her latest song, "Tambourine," at Roberto Cavalli's big bash, held at Cipriani in New York City. Cavalli-who dressed as rival designer Karl Lagerfeld-played the perfect host, stocking the bars with bottles of his eponymous vodka.

Bette Midler and Sheryl Crow made beautiful music together at Midler's 12th annual Hulaween party to benefit the New York Restoration Project. Martha Stewart and Glenn Close also got into the spirit of the evening at the glamorous gathering, held at the Waldorf Astoria hotel.

They didn't don costumes, but Ashlee Simpson and Pete Wentz played the part of the happy couple at Miami's Cameo nightclub, where they joined in the fun at the Belvedere vodka bash.

A masked Britney Spears made her best attempt to go incognito at Heidi Klum's Halloween bash at L.A.'s Green Door night club, topping off her mix and match costume with a festive sombrero.

Josh Hartnett used his experience playing Bob Dylan in the flick I'm Not There to channel the folk legend for model Gemma Ward's Imperia vodka Halloween party at the Rose Bar inside New York City's Gramercy Park hotel.

Kate Beckinsale was one hot devil as she accompanied her daughter on the trick-or-treating rounds in Los Angeles.

Gwen Stefani and Gavin Rossdale also opted for a G-rated night of trick-or-treating, taking their one and a half year old tot Kingston out house-hopping in Los Angeles.

Also on the block in L.A., Jake Gyllenhaal went undercover as a gorilla when he and Reese Witherspoon (not pictured) took Witherspoon's kids door to door to collect sweet treats.

In New York City, Liv Tyler and Royston Langdon went all out with their own costumes to take their superhero son Milo trick-or-treating.

Halloween afficionados Christina Aguilera and Jordan Bratman hit up Hollywood club Hyde for a late night fright fest. Aguilera was a sexy spiderwoman, while Bratman played the role of Count Dracula.

After several quick changes for the special Halloween episode of Live With Regis and Kelly, Kelly Ripa gave peace a chance as she took children Lola Grace and Joaquin Antonio around their New York City neighborhood.

A swashbuckling John Legend cozied up to Petra Nemcova (right) at the Roberto Cavalli bash at Cipriani. After an intimate dinner for friends, Cavalli threw open the doors to Halloween revelers and kicked off the evening's entertainment, which included a sultry acrobatics routine and a special performance by Eve.

Paris Hilton wore barely-there camouflage for the "Very Sexy Halloween" party at DJ AM's LAX nightclub in Las Vegas. Once inside, Hilton stayed in the spirit of Sin City, changing into a sexy inmate costume.

Though Sean "Diddy" Combs was a masked man at the Cavalli party in New York City-dressing up as the freedom fighter known only as "V" from the flick V for Vendetta-he still couldn't escape the paparazzi that awaited him outside Cipriani.

Jamie-Lynn Sigler channeled Factory girl Edie Sedgwick at the annual Imperia Vodka Erotica Halloween ball at Scores West in New York City. Jay-Z and Russell Simmons also stopped by the sexy soiree.

Al Roker, Tiki Barber, Matt Lauer, Meredith Vieira, Hoda Kotb and Natalie Morales dressed as the Munsters for their Today show Monster bash in New York City's Rockefeller Center.

Haylie Duff

dressed in accordance with the throwback theme at the Absolut 100 Urban Daddy Halloween Bash at Les Deux in Los Angeles. Danny Masterson DJ’d a 1920's-inspired set for Lauren Conrad, Wilmer Valderamma, Rachel Hunter and Ian Ziering.