The Biebers traveled back in time to Bedrock as they dressed up as popular characters from the show for a Halloween party on Saturday.

Hailey dressed up as an adult Pebbles Flintstone, while Justin dressed up as an adult Bamm Bamm Rubble. The couple had attended British blogger Vas J. Morgan and Michael Braun’s annual Halloween party, where they were joined by a slew of other celebrities.

The Peaches singer wore an animal-print loincloth with a brown strip of cloth wrapped around a little bone. To stay in character, he also wore a matching baseball cap. Meanwhile, the Rhode founder was dressed as a character in a PVC green top with a blue tunic and an auburn wig.

The singer was also seen the night before at Cindy Crawford and Rande Gerber’s Casamigos party in West Hollywood.

Justin and Hailey’s matched ensembles after an interview with GQ Hype last week in which the model discussed why they dress so differently.

“It’s so funny because I see so many people talk about this,” Hailey said to the site. “He may want to wear baggy sweats to dinner, and I might want to wear a tiny little dress just because that’s how I’m feeling.”

Furthermore, she said, “We can’t sit there and be like, ‘So I’m going to wear this and you’re going to wear this.’”