JUST BAG IT, BIGMOUTH! KRIS JENNER, enjoying a fun day shopping in Calabasas, bumped into her old pal PAMELA ANDERSON as both were leaving a store parking lot.

Said My Spy Witness: “Kris was so happy to meet Pam, and kept telling her that with all the attention she used to draw, she’d been hotter than a Kardashian before there were Kardashians! As the ladies got into their cars and started backing out, Kris suddenly rolled down her window and continued chatting with Pam – but their conversation was rudely interrupted by an impatient driver who suddenly honked and hollered, “HEY!…Wouldja mind moving, old lady?”

Aghast, Kris bellowed back: “Yes, I DO mind…and I’m NOT an old lady!” Sticking his head out the window, the exasperated guy barked, “I wasn’t talking to you!”…then pointed to a car behind Kris, where an addled 80-ish lady driver was creepy-crawling out

of a tight parking spot. “Kris got pretty embarrassed, and later admitted to pals she’s maybe getting a tad too touchy on the age issue,” giggled my spy. (NOTE TO KRIS: No reason you should, lady, after that waaay-hot recent photo of you laying out by a pool, all seal-sleek and sexy in a teeny-weeny bikini! YUM!)