By Isabel Jones
Updated Aug 25, 2016 @ 3:30 pm
Sofia Richie - Birthday LEAD

Nicole Richie's little sister Sofia celebrated her 18th birthday in a big way, Wednesday. The freshly-minted adult chose to enjoy her special day by partying in Hollywood with friends—including none other than Justin Bieber. The pop star and Sofia were spotted leaving celebrity nightlife hub The Nice Guy yesterday evening, sparking speculation of a budding romance. Less than two weeks ago, the duo made their friendship Instagram-official by posting shots of each other on their respective social media accounts, according to Peoplejust before Bieber deleted his account after a reported online feud with ex, Selena Gomez and her friend Hailey Baldwin.

Sofia Richie - Birthday Embed
Credit: AKM-GSI

Leaving the drama behind, Sofia ushered in her new year in style, wearing a barely there strapless white crop-top, high-waist black pants, a distressed denim jacket, and a pair of chic lace-up stilettos. Meanwhile, the "Sorry" singer donned a characteristically Bieber-esque ensemble: baseball cap, graphic tee, slouchy jeans, and a pair of white sneakers.

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Happy birthday, Sofia—18 is quite the milestone!