The former "Scorpion" actress flaunted her toned stomach while wearing a two-piece on vacation with her new husband, David Foster, and displayed some deep "KUWTK" knowledge with her cleaver caption.
Posing in a mirror, Katharine snapped a sizzling selfie while in the Maldives on Wednesday.
"David posted this while playing games on my phone," she joked. "Not sure why or how he chose it but I’m not complaining."
While several fans thought she was taking aim at her husband's age -- he's 69, she's 35 -- Katharine hit back by clarifying her post.
"Why would a 60 year old man being playing games on your phone. Just own it. You look good and you posted a pic," said one naysayer.
That's when Katharine responded, "No. no. Look up an old Kim K tweet! You'll get it."
The actress is referring to a 2015 incident where Kim claimed North West posted a sexy bikini shot of her mommy.
North was only 2 years old at the time.
Sharing the hot throwback, Kim wrote, "North posted this on IG while playing games on my phone. Not sure why or how she chose it but I'm not complaining RP."
Kim took a lot of heat from fans questioning her over whether it was actually North who posted the photo.
It seems Katharine's a pretty big fan of Kim, especially if she remembers this four-year-old detail.
Katharine & David 4 Eva!
As The Blast reported, Katharine married the Grammy winning producer in June, two years after their engagement.
They were first linked in 2017 around the time his divorced from Yolanda Foster was finalized.