Hollywood Dirt: Celebrity Halloween Photos, Khloe Kardashian’s ‘X-Factor’ Wardrobe Malfunction & More

CELEBRITIES IN THEIR HALLOWEEN COSTUMES: Here's the latest round of celebrity Halloween costume pics.  I'll start with JESSICA SIMPSON who dressed as a "wench" for Halloween, and she looked pretty freakin' hawt! I'm guessing that diet she's on is working for her...

Fiancee Eric Johnson had a Braveheart look going on, while baby Maxwell was a chicken

ELLEN DEGENERES did her show yesterday as SOFIA VERGARA, spoofing Sofia's Emmy dress look -- complete with the ripped backside ...

DWAYNE "THE ROCK" JOHNSON hit the streets as The Hulk ...

MARIAH and the kids dressed as Goldilocks and the Three Bears ...

While JENNIFER LOPEZ her man went trick or treating as hippies ...

Other photos celebs in their costumes  KIM and KOURTNEY KARDASHIAN, SANDRA BULLOCK, LEANN RIMES and her hubby, and "How I Met Your Mother" star ALYSON HANNIGAN and her family. 

KHLOE KARDASHIAN'S NIPPLE MAKES 'X-FACTOR' DEBUT: Man,those KARDASHIAN'S sure know how to get our attention. KHLOE KARDASHIAN debuted as one of the hosts of the "X Factor" last night ... and so did her nipple.

I wasn't the only who noticed, either. SIMON COWELL certainly took notice, tweeting "I think the air conditioning is on high tonight looking at Khloe. "Khloe hit up Twitter herself after the show joking ...

Meanwhile ... BRITNEY SPEARS wore ear plugs throughout the whole show. Could that be why she described nearly every performance on last night's show as "amazing"?

CELEBRITIES WITHOUT MAKEUP - HEIDI KLUM: HEIDI KLUM did the no makeup thing as part of some U.K. campaign encouraging women to go without their warpaint to help raise money for disadvantaged children.