The stars are out for Halloween!

Justin Bieber, Jessica Alba, Austin Butler and Paris Hilton were among some of the celebrities who attended Cindy Crawford and Rande Gerber’s annual Casamigos Halloween party in Los Angeles on Friday night.

The star-studded event was organized by the tequila brand, which is co-owned by Rande, 61, and George Clooney, who was not in attendance.

Among the other guests spotted at the Halloween bash were Megan Fox, Machine Gun Kelly, Julianne Hough, Paris Jackson, Victoria Justice, Jason and Brett Oppenheim, Edward Norton, Sarah Hyland, Alessandra Ambrosio, Jenna Dewan, Glen Powell and Wells Adams.

Alba and Hilton, both 42, paid homage to Britney Spears with their outfits at the bash, following the release of the singer’s memoir, The Woman In Me, earlier this week.

Both wore costumes inspired by the music video for Spears’ 2003 hit “Toxic,” with Alba wearing a sheer jumpsuit with sparkling rhinestones and a long blonde wig, as Hilton donned Spear’s infamous blue stewardess dress with a matching hat.

The businesswoman was accompanied by her husband, Carter Reum, who dressed as a pilot.

Bieber, 29, opted for a fun look at the party, sporting a beach-themed outfit made up of neon yellow flippers and a snorkel, which he paired with a pink flower-print shirt and matching pink shorts. 

Butler, 32, got deep into character as he attended the bash as Andy Warhol in a floppy white wig, black sunglasses and a leather jacket.

The Elvis actor was joined by girlfriend Kaia Gerber, who came as 1960s model and Warhol’s muse, Edie Sedgwick. 

The pair — who made their first public appearance as a couple in March 2022 — posed with Kaia’s brother Presley Gerber and parents Crawford, 57, and Rande at the party.

Rande and Crawford were dressed up as Sandy Olsson and Danny Zuko from the 1977 film Grease, donning matching all-black outfits with leather jackets.

Crawford also wore a curly blonde wig, red lipstick and matching red peep-toe pumps.

Fox, 37, and Kelly, 33, caused a stir with their bloody costumes, as they came dressed as characters from the 2004 film Kill Bill. 

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Kelly wore a blood-stained yellow jumpsuit and held a katana sword as Uma Thurman’s character The Bride.

Fox, meanwhile, sported a school uniform in character as teen assassin Gogo Yubari from the film. 

Jackson, 26, for her part, dressed up as Old Gregg from the British series The Mighty Boosh in a pink tutu, black top, and a white tie with matching platform boots. 

The musician and actress wore a green wig and had a painted white face, red lips and a draw-on mustache.