Oscar Dirt -- What REALLY Happened Last Night ...

So here's how it went down ... an X17 spy inside CAA agent Patrick Whitesall's Oscar after-party last night told use this:

"Everybody and their mother was there ... Leo and Bar Rafaeli were hand-in-hand, arm-in-arm, lovey-dovey all night long.

Paris was WASTED drunk and got into an argument with some girl and then had a fight with Stavros. He kept trying to walk away from her and she chased him down.

Nicky Hilton and David Katzenberg were happy together.

Vince Vaughn showed up with friends, drunk as a skunk.

Naomi Campbell was hanging out with Kimora Lee Simmons.

Jessica Biel was handing out with Justin's friend, club promoter Pantera Sarah.

Lindsay was drinking WATER (for real, y'all!) and smoking cigarettes. [You go, girl! And you're lookin' fine, btw ...]





Cameron Diaz spent some time hanging out and flirting with Djimon Hounsou.











Nicole and Joel were all over each other the entire night." - Surprise!





Sean Penn was hanging out with Kid Rock the whole night (they enjoyed some 'party favors' together, according to another source).


more pix of the partiers inside ...