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(From left to right) Amal Clooney, Rita Ora, Kim Kardashian and Ariel Winter.Instagram

Halloween is here and celebrities are out to shock, surprise and amaze everybody else with their crazy costumes. Recently, George Clooney and Rande Gerber hosted the Casamigos Halloween Party in California and the event saw just the right amount of glitz and jazz when it came to costumes.

Also read: From racist outfits to sexualising child characters: Halloween costumes to avoid in 2017

Present at the party were Amal Clooney and Cindy Crawford and the two close friends donned themselves with the classic 1970's chic glamour. It was the first time that Amal was seen at a public event in anything other than her sophisticated gowns and boy, did she surprise!

Kim Kardashian pulled off all the right kind of Cher vibes, mingled with the 1970's aura. She and bff Jonathan Cheban dressed up as Cher and Sonny and partied so flawlessly, that the LGBTQ icon herself congratulated Kim on how well she pulled the look off.

While Kim's tiny waist and toned abs in a yellow belly dancer outfit stole the show, Alessandra Ambrosio owned Charlie's Angels meet ABBA inspired outfit that bared the supermodel's mid-riff, gave her a tough competition.

Clooney and Gerber weren't the only ones hosting parties as Just Jared's 6th Annual Halloween Party saw some iconic costumes of its own. Modern Family actress Ariel Winter who is known for her controversial outfits, sported the signature sexy skeleton look.

Bone-print leotards with fishnets, knee-high boots and an equally spooky make up only boosted the Halloween aura about her. Joining her in the scary skeleton department was Victoria's Secret model Sara Sampaio, who pulled off a unique mid-plastic surgery look.

Isla Fisher brought in her own personal element of vibrancy, sporting a unicorn horn and rainbow wig, and it complimented Australian model Shanina Shaik's silver bodysuit, blue lipstick sporting sexy alien look.

A post shared by Amal Clooney (@amalclooney) on

Groovy Baby ? 70’s #halloween #Cher #styledbyinspiresmi

A post shared by Alessandra Ambrosio (@alessandraambrosio) on


A post shared by Isla Fisher (@islafisher) on

I’ll give you guys my surgeon contact!! He’s the best!! #halloween17

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A post shared by SHANINA SHAIK (@shaninamshaik) on

Ryan Seacrest happened to tease fans via an Instagram video, with a sneak peek into him getting transformed into a woman – full with a red dress and flowing wig, for his show Kelly and Ryan.

Let’s just say I have a newfound respect for people who wear heels. #LIVEHalloween

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But his wasn't the only gender-bent costume as Teen Wolf star Colton Haynes pulled off a classy, voluptuous Marge Simpson.

Excited to host @FreixenetUSA 2nd Annual Black Magic Halloween Affair tonight! #ad #BubsInTheClub #FXCava #CavaWeen

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The Metropolitan Museum of Art's held its 'All Hallows' Eve' benefit, where the dress code read "mystical costume attire" – leaving it totally up to the guests to make and dress up whatever they deduced from the theme.

Jessica Chastain, Karlie Kloss, Joan Smalls and Ellie Goulding were among the many faces attending the event. While Jessica was a morbid, pale corpse bride, Joan portrayed a whole other side of the spectrum, dressed as a coy Minnie Mouse.

Minnie by Me... Halloween @ the Met ?

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However, Rita Ora probably won this Halloween with her sexy, iconic version of Poison Ivy. The singer attended the Kiss House Party Live event at the SSE Wembley Arena in London on Thursday and her green fishnet stockings stole the show.