Kelly Clarkson Says Her Ex-Manager Told Her To Get A Boob Job

Kelly Clarkson isn’t holding back -- firing off at her ex-manager who once suggested she get a boob job ... and her response back to him definitely hit all the right notes!

The singer was mid-show at her "Studio Sessions" at Caesars Palace in Las Vegas, Saturday night when her monologue turned to her cleavage ... after joking she was spilling out of her low-cut look, Kelly reflected, "I had a d*ck manager once tell me to get a boob job!"

Kelly was totally floored by the so-called "advice" ... telling him she suggested he get a 'd*ck job" instead.

She doubled down, saying she’s always been perfectly happy with her "itty-bitty titties" ... and reminding fans that, yes, people in the industry really do say wild stuff like that all the time.

Kelly said the whole thing’s gotten out of hand -- joking that everyone in the industry looks like they’re the villains in the "The Hunger Games," acting like it’s windy every day with those tight faces. She made a point to say aging’s a privilege, and not everyone gets to be old.