Country cupcake CARRIE UNDERWOOD shrieked four-letter unprintables at a Dirty Old Man she caught sneaking and peeking behind her as she sashayed through a Victoria’s Secret store in Puyallup, Wash., shopping for sexy undies.

The creep kept ducking behind mannequins and displays, spying on curvy Carrie as she held bras, panties, corsets and camisoles up to her heavenly bod.

A sharp-eyed female customer finally ratted the guy out to the store manager, who came running to confront him – just as Carrie caught on herself and screamed at the rattled perv: “What’s your effing problem!…I can’t even shop for underwear anymore without being hassled. Get the hell away from me!”

Freaked, the old freak fled for the street. Carrie calmed right down, and wound up spending $1,000-plus on push-up bras and panties in leopard, Dalmatian and blue tiger prints.