Rob Lowe Starstruck ... by TMZ Photog!

The former Brat Packer was spotted outside Waverly Inn & Garden in New York last night, where he was genuinely elated to have a run-in with our photog, saying, "I feel like a big, fat f**king star now!"

Uma Thurman was a different story -- leaving the restaurant with a mystery man, covering her face and avoiding any acknowledgment of the camera's existence.

TMZ also caught Uma's "Kill Bill" co-star Lucy Liu -- chatting up a few chefs through Waverly's back door, plus Jay-Z and Masi Oka (aka Hiro Nakamura) who teleported to Butter, and Miss Dita Von Teese, who left her pasties at home and went out to The Inn in a sparkly red number.