Looks like Lauren Conrad has more BFF drama in the upcoming fourth season of The Hills, which premieres August 18 on MTV.

Friend-turned-rival of the season: Stephanie Pratt.

The reason? Steph moves in on LC's new boy Doug Reinhardt.

Meanwhile, Lo Bosworth and Audrina Patridge try to sort out their own tensions, Whitney Port has a new man in her life, and Heidi Montag and Spencer Pratt fight with their siblings - and each other.

All that ca-razy drama and a whole lot more makes the Season 4 trailer for The Hills a definite must-see. Peep it below: