The mother-of-three -- who, despite being romantically linked to Bieber in 2015, has been friends and neighbors with the musician for years -- donned a cleavage-baring, sheer black lace outfit when she showed up with Kris Jenner's boyfriend, Corey Gamble, at The Nice Guy in West Hollywood, California.
A source tells ET that while Kardashian chatted with the 21-year-old pop star at the party, the two did not show any public displays of affection. Bieber instead stuck close by his circle of friends, which included his manager, Scooter Braun.
Bieber's post-GRAMMYs outfit included a cheetah-print jacket that he paired with an all-black ensemble and a backwards hat. There were several videos posted to Instagram of the "Sorry" singer partying and speaking to the crowd during the night. That same evening, Kardashian, Gamble and Bieber were also all spotted at West Hollywood hot spot, 1 Oak.
Kardashian wasn't the only star celebrating Bieber's big win. ET caught up with Selena Gomez, who was thrilled about her ex-boyfriend's accolade. "I'm very happy for him. Honestly, so cool," she told ET after Bieber won for his dance track, "Where Are U Now," which features Skrillex and Diplo. "They have such a cool energy amongst all of them to be able to create something like that. It's really great."