Paris Hilton, Nicole Richie: Just Like Old, Annoying Times

If there's one thing the Simple Life duo knows how to do, it's act really, really annoying and feud with each other for months on end and for no reason.

But if there's a second thing Paris Hilton and Nicole Richie know how to do, it's work the room.

The newly reunited gruesome twosome was spotted in Brentwood Friday night, at party-planner Lara Shriftman's book party for Party Confidential.

Yup, the one-time BFFs, one-time mortal enemies and current BFFs Paris and Nicole made the rounds there for an hour, doing the whole socialite thing, before hitting the road. Spies say the two mingled with the large crowd, going person to person, hand-in-hand most of the time.

Nicole's freshly-darkened locks all but confirm that she was the "mystery friend" of Paris (left), who was seen hiding under a jacket as they ran into the Hollywood hotspot Hyde last Thursday.

The projectile vomiting and collapsing on the floor were also pretty good indicators.

This whole Paris-Nicole union is just plain wrong in our opinion. Wonder what Samuel Plouchart thinks of all this.