The Stars Go Trick-or-Treating

Ashley Greene and Kellan Lutz

Eclipse

stars Kellan Lutz and Ashley Greene celebrated fright night in Sin City, hosting the Yelloween party at Tao Las Vegas. "So excited to dress up for Halloween and my costume!" Greene Tweeted about her peacock costume the night before the bash-while Lutz went as Batman sidekick Robin.

Brad Pitt, Angelina Jolie, Zahara and Shiloh

Fright night was a family affair for the Jolie-Pitts, who hit the streets of L.A. for some trick-or-treating. While Brad dressed up as DJ Lance Rock from the hip kids show Yo Gabba Gabba, Zahara played Bat Girl, Shiloh kept her tomboy image intact as a fighter pilot and mom Angelina sported some bloody face paint.

Michelle Obama

First lady Michelle Obama made the purr-fect catwoman when she paired kitten ears with a leopard-print sweater to hand out candy-the selection included dried fruit and M&M's according to HuffingtonPost.com-to local school children at the White House. President Obama exercised his right not to dress up, opting for a more casual ensemble of a sweater and dress pants.

Miley Cyrus

She didn't get the night off, but Miley Cyrus gave peace a chance when she channeled Pocahontas to perform at a special Halloween concert at Freedom Hall in Louisville Kentucky.

Heidi Klum and Jessica Alba

Though she gave birth to daughter Lou Sulola Samuel just a few short weeks ago, nothing could stop Heidi Klum-almost unrecognizable in her crow costume-from hosting her annual Halloween bash. The Project Runway host welcomed guests Paris Hilton, Jessica Lowndes and a Dora the Explorer costumed Jessica Alba to Hollywood's Voyeur Club for the fright night fete, presented by MSN and SKYY Vodka.

Nick Cannon and Mariah Carey

Known for their couples costumes-last year they attended a party as milk and cookies- Nick Cannon and Mariah Carey were in Halloween heaven when they attended a party at New York City's M2 Ultra Lounge.

Gwen Stefani

Dressed as a glamorous gunslinger, Gwen Stefani toted her tiny dinosaur, son Zuma-already enjoying one of his treats-to a Halloween party in Los Angeles.

Michelle Trachtenberg

Gossip Girl

star Michelle Trachtenberg marked Halloween as Marie Antoinette at the 2033: Adult Playground bash, held at New York City hot spot 1Oak.

Blake Lively and Scott Sartiano

Also at 1Oak for the Svedka Vodka bash, sexy flight attendant Blake Lively posed with club owner Scott Sartiano before heading inside to join boyfriend Penn Badgley for the festivities.

Christina Aguilera

Christina Aguilera

's son Max was her skeletal sidekick when the duo went trick-or-treating in L.A.'s tony Brentwood neighborhood.