Kristen Cavallari Dating Ex of Nicole Richie ... as Richie Dates Ex of Cavallari

Follow all that? It's simple, really:

Kristin Cavallari used to date Brody Jenner. It was a Laguna Beach thing. Then, they broke up.

After that, Nicole Richie began tanging Jenner, although Brody had trouble distinguishing between Richie and the bed sheet beneath him.

Now, Cavallari is cozying up to Richie's ex-fiance, Adam Goldstein. Also known as DJ AM. Naturally.

On Tuesday night, the 33-year-old Goldstein arrived in the same car as the 19-year-old Cavalleri to a party. He hung back as she preened on the red carpet, tugging up her strapless dress.

"I don't want a Tara Reid moment," Cavallari said to photographers. "I'm not taped, that's the thing. That's why I'm pulling!"

Cavallari then claimed she was there with "um, my friend Charlene." Apparently Laguna Beach doesn't teach you how to lie well.

Goldstein eventually joined Kristin inside and the two were seen cuddling until 4 a.m.