Halloween is in full swing in Hollywood and the stars are dressed to scare and impress. While Halloween is officially marked on the calendar for Oct. 31, celebrities will be celebrating all weekend. Here Jessica Alba dresses up as Britney Spears from the “Toxic” music video and Kelly Sawyer Patricof attends as Spears from the “… Baby One More Time” music video. Next to them, Edward Norton and Shauna Robertson channel David and Victoria Beckham at the annual Casamigos Halloween party on Oct. 27. Scroll through for some of the best spooky, sexy and surreal costumes. Matt Winkelmeyer, Getty Images For Casamigos Megan Fox and Machine Gun Kelly as Beatrix Kiddo and Gogo Yubari from “Kill Bill” at Casamigos’ Halloween party. Matt Winkelmeyer, Getty Images For Casamigos Cindy Crawford (center) and Rande Gerber (far right) hang out with their kids Presley Gerber (second from right) and Kaia Gerber (second from left) at the Casamigos Halloween party. Kaia’s boyfriend Austin Butler (far left) joined the group photo. Matt Winkelmeyer, Getty Images For Casamigos Paris Hilton arrives at the Casamigos party as Britney Spears from the “Toxic” music video. Alberto E. Rodriguez, WireImage David Spade carries a sword as he enters Casamigos’ Halloween party. Alberto E. Rodriguez, WireImage Chord Overstreet (left) and Glen Powell are rival race car drivers at the Casamigos Halloween party. Matt Winkelmeyer, Getty Images For Casamigos Justin Bieber gears up for summer 2024 in beach attire, scuba shoes and a snorkel at Casamigos’ Halloween party. Matt Winkelmeyer, Getty Images For Casamigos Jenna Dewan as Kim and Steve Kazee as Edward Scissorhands from the 1990 Tim Burton film at the Casamigos Halloween party. Matt Winkelmeyer, Getty Images For Casamigos Tyga is unrecognizable as the clown from “Terrifier” at the Casamigos Halloween party. Alberto E. Rodriguez, WireImage Gavin Rossdale and his date attend the Casamigos Halloween party in all black. Matt Winkelmeyer, Getty Images For Casamigos Kelsea Ballerini dresses as a cowgirl Barbie for her Halloween costume party at Beauty & Essex in New York City on Oct. 25. Dimitrios Kambouris, Getty Images