Kelly Clarkson Jokes About Having 'Small' Boobs on Stage

Kelly Clarkson's got a big voice, but when it comes to her assets ... not so much ... at least according to her.

The singer was chatting with the audience at her Caesars Palace residency in Las Vegas on Saturday when she got worried her boobs were gonna pop right out of her shirt ... after a gust of wind exposed her bra.

Kelly joked ... "They're too small, they won't come out. You're fine," insisting she wasn't actually on the verge of a wardrobe malfunction.

As soon as the words came out of her mouth, she clarified that her tiny boobs are "perfect" ... noting she didn't want to piss off the universe.