EXCLUSIVE: Inside George Clooney's A-List Halloween Party -- Including Leonardo DiCaprio and Tobey Maguire's W

The stars definitely brought their A-game with their quirky ensembles Friday night.

Leonardo DiCaprio, The Wolf of Beverly Hills!

Dressed in a simple pair of light-wash jeans, a plaid button-up and furry wolf mask, The Wolf of Wall Street star led a pack of four fellow masked men into Friday's Casamigos Tequila Halloween party thrown by co-founders George Clooney, Rande Gerber and Mike Meldman.

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According to an eyewitness, DiCaprio arrived close to midnight and was having a blast inside the star-studded bash with his close pal, Tobey Maguire. The Spider-Man star, who called it quits with Jennifer Meyer after nine years of marriage just last week, covered his face with a monkey mask and was no longer wearing his wedding ring.

DiCaprio seemed to be in great spirits, the eyewitness noted. He was bouncing back and forth from the dance floor to the bar and mingling with everyone in sight. At one point, the 41-year-old actor and Robin Thicke couldn't contain their laughter as they busted out their best dance moves.

Also making a memorable entrance? Casamigos Tequila co-founder, Rande Gerber, and his strikingly beautiful family -- his wife, Cindy Crawford, and their two children, Presley and Kaia. "Everyone stopped to see their punk rock looks," the eyewitness told ET, revealing that the entire Gerber clan posed for photos and chatted with guests.

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Lauren Conrad also turned heads at the festive fete, rocking a DIY circus performer get-up. The eyewitness tells ET that The Hills alum was chatting with Linda Thompson, the mother of her former co-star and ex-boyfriend, Brody Jenner.

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Like Conrad, Jenna Dewan Tatum was all about the custom-made costume this year, sparkling her way through the party in a glitzy unicorn ensemble.

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Her look was a far cry from what Seth MacFarlane was sporting -- an Oscar the Grouch one-piece, complete with the word "Scram!" on the garbage can.

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Others in attendance included James Corden, Lisa Rinna, Alessandra Ambrosio Sylvester Stallone, Mark Consuelos, Hilary Duff, David Spade, Ryan Seacrest and Kelsey Grammer.

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