Kourtney Kardashian was recently sighted with Justin Bieber, who sparked romance rumors with her in 2015. They both helped celebrate mutual friend and restaurant owner David Grutman's 36th birthday on Sunday in Miami at his STORY nightclub. 22-year-old Bieber was seen leading Kardashian into the DJ booth, and the two later talked at her table. Bieber also led the crowd to sing a "Happy Birthday" song to Grutman.