Lifestyle Style Justin & Hailey Bieber, Demi Lovato, Halsey and More Attend L.A. Halloween Party — See the Photos! The Biebers rocked 'Flinstones' attire, while Lovato looked classically cool in a Disney costume By Brenton Blanchet Brenton Blanchet Brenton Blanchet is a writer-reporter at PEOPLE. He has been working at PEOPLE since 2022. Brenton's work has previously appeared in Billboard, Pigeons & Planes and Complex. People Editorial Guidelines Updated on October 30, 2023 04:40PM EDT Justin and Hailey Bieber, Demi Lovato, Halsey. Photo: Rachpoot/Bauer-Griffin/GC Images The stars are out this spooky season! Justin and Hailey Bieber, Paris Hilton, Demi Lovato, Jodie Turner-Smith and Halsey were among some of the celebrities who attended Vas Morgan and Michael Braun's Halloween Party in Los Angeles on Saturday night. The Biebers — who are no strangers to getting into the Halloween spirit — stepped out as Fred Flinstone and his daughter, Pebbles Flintstone. Justin, 29, went shirtless while wearing the cartoon character's signature bottoms, and he opted for a backward hat of the same pattern to give the look some flair. Hailey, 26, for her part, wore a skin-tight shirt and skirt, with patterns matching the cartoon character she was embodying. She completed the look with a red wig to tie it all in. Justin and Hailey Bieber attend Vas Morgan and Michael Braun's Halloween Party. Rachpoot/Bauer-Griffin/GC Images Lovato, 31, also decided to channel some classic animation, dressing as Snow White from Disney's 1937's classic, Snow White and the Seven Dwarfs. The "Heart Attack" singer accessorized her look with a red bow on her head and vibrant red lipstick. Demi Lovato attends as Morgan and Michael Braun's Halloween Party. Rachpoot/Bauer-Griffin/GC Images Celebrities Attend Rande Gerber and Cindy Crawford's Annual Casamigos Halloween Party in L.A. Halsey, 29, dressed up as a siren for the festivities by wearing a see-through skirt, a white bikini top and plenty of seashell-like accessories. And while characters and mythical creatures appeared to be popular at the gathering, Hilton, 42, decided to go the pop-culture route. Halsey attends Vas Morgan and Michael Braun's Halloween Party. Rachpoot/Bauer-Griffin/GC Images Just a day after dressing up as Britney Spears at the Casamigos Halloween party, Hilton channeled another pop star on Saturday: Katy Perry. For that costume, Hilton rocked Perry's mushroom get-up, which the singer dons during one part of her Las Vegas Residency, Play. Paris Hilton attends Vas Morgan and Michael Braun's Halloween Party. Rachpoot/Bauer-Griffin/GC Images Machine Gun Kelly and Megan Fox also attended the party, just a day after the duo opted for Kill Bill-inspired costumes at the Casamigos bash. At the Saturday event, the pair sported costumes from Deathnote. For his look, Kelly, 33, spiked his hair, wore all-back and went all-out with the face makeup to put on his best Ryuk, while Fox, 37, held her own "Deathnote" to channel the manga. Machine Gun Kelly and Megan Fox Wear Kill Bill-Inspired Costumes for Casamigos Halloween Party in L.A. Machine Gun Kelly and Megan Fox spotted arriving to Vas Morgan and Michael Braun's Halloween Party. Rachpoot/Bauer-Griffin/GC Images Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. The night out also featured appearances from the likes of Paris Jackson, Casey Affleck and Kate Beckinsale, who went as the iconic Barbarella.