Ah, there's nothing like a good ol' fashioned Instagam Ass-Off.

Mothers Kim Kardashian and Blac Chyna took a break from working out to work it in front of the mirror, which naturally brought out her trusty selfie-taker.

"Getting right for the new year," Kim K wrote in the accompanying caption.

The 33-year-old attention expert has been expectedly obsessed with assuring her adoring rubberneckers that her most prized assets are back to pre-baby form.

[screengrab via Instagram]