Bieber says she was inspired by Rihanna for her Coachella look last year — a Rangers jersey with diamond rings and neon green nails. “She does that glam tomboy thing really well. That’s why I like to do a big jersey with diamond necklaces. … Rihanna is the queen of that, though. I made myself believe I could pull it off, that’s why I can pull it off,” the model says while sporting a bedazzled “Bieber” nameplate necklace with a Marina Moscone fall/winter 2019 blue coat and cuffed jeans

Now the 22-year-old (who has landed sponsorships with Bare Minerals, Adidas and H&M) is putting her fashion and modeling experience toward a more personal collection: a Roxy swimwear collab with her friend, Hawaiian pro surfer Kelia Moniz, called Sister.

The pair met two years ago through Moniz’s now-husband Joe Termini. “We met when they started dating and we’ve been friends ever since,” Bieber says. “I kind of like gravitated toward Kelia. I was like ‘Oh, this is your girlfriend? She’s so epic. We’re going to be best friends.’” Moniz, 26, tells THR that she later moved to Brooklyn, New York, with Termini and lived “basically next door” to Bieber. “So she was one of my only friends.”

Fast forward to New Year’s Eve 2018, when the friends rang in the New Year in Hawaii with Hailey’s husband, Justin Bieber, and then to Tuesday, when the friends launched their Sister Collection with lifestyle brand Roxy in Malibu. Bieber and Moniz celebrated with a cocktail party at Little Beach House Malibu and, ahead of the party, talked with THR at Palisades Village VIP Suite about their friendship and fashion inspirations.