The "Love yourself" singer was in Florida for his show, and went to the STORY nightclub after the concert, where he sang "Happy Birthday" to the venue's boss Dave Grutman.
A video of Bieber in the DJ booth has been uploaded by the club on Instagram, with the singer showing off his moves.
The "Keeping Up With the Kardashians" star was reportedly at the venue to celebrate Dave's birthday. At one point, Bieber reportedly pulled Kardashian up to the booth where they chatted.
The report comes after allegations earlier this year that the 36-year-old mother of three had been dating the singer.
Bieber and Kardashian were rumoured to be seeing each other after the "Keeping Up With the Kardashians" star was spotted at one of his concerts in March, which came after they were linked last year.
According to sources, their relationship had been "on and off" for a few months.