Their television slogan may be the 'Power of the K' but putting family first loses out to the power of the dollar it seems.
Kylie Jenner broke Kardashian ranks to make herself some money by promoting a cut-price denim line, despite sister Khloe Kardashian having her own jean company.
The 19-year-old put on a very booty-ful display on her Instagram to promote some curve-highlighting pants.
In the snap, Kylie sits on her bed looking over her shoulder at the camera wearing a pair of Fashion Nova jeans with a taupe long sleeve top tucked into them.
However, her denim-clad derriere ensured all eyes are on her seemingly-impossible proportions.
With the high-waisted jeans highlighting her tiny waist, her shapely rear end looks even more monumental than usual.
In fact, her booty makes sister Kim Kardashian's famous rump seem averagely sized.
Kylie captioned the picture: "Obsessed with my new @fashionnova jeans. Get them at FashionNova.com."
Despite the millionaire teen being surrounded in Hermes boxes, the jeans cost just a fraction of designer duds, namely $35.
Initially, Kylie did not add the hashtags #ad or #spon to her post, which has seen the reality star and her family accused of being deceptive about the paid-for posts in the past.
However, facing off with Federal Trade Commission may be the least of Kylie's problems.
She may find herself facing the wrath of sister Khloe - and even brother-in-law Kanye West - first.
Kylie's post is an endorsement of a cut-price competitor to Khloe's range Good American.
The jeans - which like Good American are US-made - also look a lot like those sold by her big sister but cost a quarter of what Khloe's do.
Kanye may also be a little unimpressed with Kylie once again, as Fashion Nova sells perspex heel shoes that are almost identical to Kanye's Yeezy Season 2 Lucite heeled sandals.
Fashion Nova's are $32.99 and Kanye's are currently sold out but were $595 but then were reissued for $495.
Kanye and Kylie famously had a falling out earlier this year after she made a deal with footwear company Puma who are in competition with Adidas, whom the rapper is aligned.