Sam Smith Jacks Justin Comb's Uber

10/25/2015 6:59 AM PDT

It's undisputed who's higher up on the Uber food chain ... Sam Smith towers over Diddy's son.

Sam and Justin Combs were leaving 1OAK in WeHo separately after catching a Travis Scott concert.

Sam was led out by some handlers, right into the back seat of an Uber.  When he left, it became clear ... it wasn't his.

We got a good reaction from Justin.