No wonder Audrina Patridge isn't a fan of Kristin Cavallari.

In this exclusive preview of the sixth season premiere of MTV's The Hills (premiering Tuesday), Cavallari, 22, dines with Patridge's on-and-off love Justin "Bobby" Brescia.

"She clearly is in love with you," Cavallari tells him.

Hills previews indicate that Cavallari goes after Brescia, upsetting Patridge, 24.

"It's fun to play the bitch," Cavallari told earlier this month.