sunglasses twilight Kristen Stewart shirt jacketBefore she left LA with Rob, Kristen Stewart was caught having a heated conversation with someone on the balcony of her Beverly Hills hotel Sunday while smoking a cigarette.

Hmmm, we wonder who she could be talking to -- Perhaps Rob, to arrange another rendez-vous at the airport?

Geez, life for Kristen must be so stressful! Talk about your hit movie, take gorgeous pictures, avoid the topic of your boyfriend -- no wonder she needs constant smoke breaks!

But smoking wasn't the only thing she was doing out there...