George Clooney, Rande Gerber Host Wild Halloween Party

George Clooney, Rande Gerber, and Michael Meldman threw a killer 1970's themed Halloween Party in West Hollywood Friday night. Tons of A-list celebrities showed up in full costume to enjoy music by DJ Cassidy and margaritas made with Casamigos, the tequila company George, Rande, and Michael founded and then sold for up to a billion dollars. Click through the gallery for a peek inside what's being called the "party of the year" and check out the stars in their seventies inspired costumes.

Amal Clooney dressed to the nines in disco-era glam, was on hand to help host the epic event. Amal looked thin and fit after having given birth to twins Ella and Alexander Clooney 4 months ago.

Supermodel and business woman Cindy Crawford, 51, and her entertainment businessman husband Rande Gerber rocked the seventies look perfectly.

Kaia Gerber, 16 and big brother Presley Gerber, 18, were model guests at their parents' party.

Kim Kardashian West, 37, and her BFF Jonathan Cheban make a perfect pair as Sonny and Cher. Cher later tweeted her seal of approval to the reality star.  

The Voice coach Adam Levine channeled his inner disco diva and was joined by George and Rande's business partner Michael Meldman. Adam wowed the crowd by joining his band Maroon 5 for a surprise performance.

Retired mixed martial artist and champion UFC fighter Chuck Liddell, 47, and Heidi Northcott, 37, are making the party rounds. The couple attended Maxim magazine's annual Halloween bash last week.

Model Joanna Krupa, 38, made a perfect Sandy from the blockbuster 1978 film Grease.

Mad Men star Jon Hamm looked as handsome as ever in an all white suit.

What do Game of Thrones star Peter Dinklage, Hole frontwoman Courtney Love, and comedian/actor David Spade have in common? Quite possibly nothing! But the three were all smiles at the Casamigos party where they posed together for pictures.