Britney: I Was Being Sarcastic, I Know My Sis is Preggo

A source close to Britney Spears tells TMZ that the popwreck's comment to our cameras last night denying sister Jamie Lynn's pregnancy was a joke. She was "being sarcastic," we're told. "She knows." Hope so!

Brit had been out on a late-night shopping excursion when photogs asked how she felt about being an auntie. She replied, "My sister's not pregnant!" much to the surprise of the throng around her.

Britney's not that dumb. She's just not a comic.