"I can't wait to perform the Caesarean!" her Twilight leading man teased back.
Calm down, Twilight Nation! It was all part of the banter at the July 23 Twilight Saga: New Moon panel at Comic-Con International, the comic book and popular arts convention in San Diego.
Kristen was coyly referencing Breaking Dawn (spoiler alert!), the fourth book in Stephenie Meyers' vampire saga (in which Bella Swan, Kristen's character, ends up "with child"), while Rob -- aka Edward Cullen -- was just being goofy for about 6,500 fanatics who camped out for a glimpse of their idols.
The event marked the first time Rob and Kristen were seen together since June (one report says they met in private the night before), when their burgeoning romance halted -- he left for NYC to film Remember Me and she stayed in L.A. for The Runaways.
"She stressed over what to wear and what to say when she saw him," says the insider. "They did hug, but Kristen admitted to friends that it felt awkward."
That was evident at the panel discussion when they ignored the off-camera chemistry questions, and later when OK! caught up with them at The Twilight Experience at the local multiplex: Kristen played with her hair and Rob nibbled the stems of his Ray-Bans.
They revealed even more when discussing their roles: Was Rob thinking of his fling with Emilie de Ravin while citing a "very relatable" New Moon moment when Edward realizes he loves Bella " too much" and "deliberately starts breakin up their relationship"? And what did Kristen mean when she said Bella "doesn't have to explain herself" when she changes her mind because "she just feels what she feels"? Eclipse starts shooting in August. Stay tuned!
For more on Rob and Kristen, pick up the new issue of OK!, on sale everywhere Thursday!