Cameron Diaz camdrew113.jpg Say it ain't so!

According to OK! Magazine, BFFs Drew Barrymore and Cameron Diaz aren't so chummy anymore! At the CAA Golden Globes afterparty on Sunday night, the two actresses showed up separately, and a source for the mag says, "Both Cameron and Drew were at the party but neither one spoke to each other!" Another witness added, "They were on opposite sides of the room the entire night."

We're shocked that the "Charlie's Angels" co-stars might have beef with one another, so we're wondering what could have caused this. Think the ladies have just drifted apart in recent months? Or is Cam spending too much time with her model boyfriend, Paul Sculfor? Either way, we're determined to get to the bottom of this!

And get this - apparently Drew wasn't the only one who gave Cam the cold shoulder! A source tells OK! that at one point during the party, "Leonardo DiCaprio saw Cameron coming towards him and he immediately made a U-turn and walked in the opposite direction."

What's going on here?!