This is sort of an odd crew to be hanging out together (minus the couple in the group) … Justin Bieber, Selena Gomez, Katy Perry and Robert Pattinson partied it up on Tuesday night.

The four of them went to the opening of a new club that David Arquette opened.  The club is called Bootsy Bellows.  The four celebs went to Chateau Marmont first, then they all got into Justin’s Mercedes minivan and went to David’s club.

Well, there was one little problem that happened Tuesday night.  After Justin, Selena, and Katy got into the minivan, the door shut.  Robert was left standing outside of the van.  After a few minutes, the van door opened up and Robert got in.  People that saw it happened said Robert had a good sense of humor about the whole thing.