Justin Bieber may have had a bad time at his Comedy Central roast on Saturday, but it wasn't as bad a time as one celeb had at JB's 21st birthday bash on Sunday!
Apparently, David Arquette was thrown out of Justin's rooftop party at Nobu in Las Vegas because the 43-year-old actor kept trying to start fights.
Oh yeah, and he wasn't just sent packing once… he got booted TWICE!
We're hearing that David was drunkenly bad talking Justin and was kicked out a first time, then reportedly proceeded to sneak back in and charge at the birthday boy!
[ Related: Distasteful Paul Walker Jokes To Be Edited Out Of JB's Roast! ]
Since it was a private party, Justin didn't have any security guards with him and needed a friends help to personally remove Courteney Cox's party-goin' ex from the event.
Hopefully they're both doing better after having a couple days to recuperate, but…
We just want to know how David was possibly invited in the first place!?
Tags: alcohol, birthday party, comedy central, courteney cox, david arquette, gifs, justin bieber, las vegas, party poppin', roast, sin city