The 19-year-old star appears to have moved on from Selena Gomez and was seen laughing and joking with the allegedly newly-single blonde at Beacher's Madhouse at the Roosevelt Hotel in Los Angeles.
The 'Take You' hitmaker rocked up at the swanky venue at 1.50 AM and made a beeline for Miley's table.
According to gossip website TMZ, Miley - who is said to have parted ways with her fiancé Liam Hemsworth last month - hung out with Justin for around 15 minutes before they were caught on camera leaving together shortly after 2 AM.
The pair have been friends for years, but their late night rendezvous comes just hours after Justin's distinctive leopard-spotted Audi was seen pulling out of Miley's Los Angeles mansion's driveway.
While the showbiz pals are rumoured to be plotting a musical collaboration together, sources have claimed in the past that Miley and Justin have history and their chemistry was making Justin's then-girlfriend Selena jealous.
An insider told Life & Style: ''Justin and Miley hooked up a few years ago. Then he started dating Selena.
''It created this whole jealously thing between them. Now Selena doesn't want Justin anywhere near Miley -- and they've been fighting about it!''