Jenner, 19, and Kardashian, 36, went topless and sported identical looks in a promo for their KKW x Kylie makeup collection.
"COMING SOON @kyliecosmetics #KKW," Jenner captioned the post for her 92 million Instagram followers.
Jenner launched Kylie Cosmetics in 2016 following the success of her Kylie Lip Kits. She previously collaborated with sister Khloe Kardashian on the KoKo Kollection by Kylie Cosmetics, a set of lip products.
"The Koko Kollection. The first Kylie Cosmetics kollaboration. Can't wait for everyone to experience this gorgeous range of lip products created by @khloekardashian," the star announced in November.
Jenner will also stay busy with her Keeping Up with the Kardashians spinoff, The Life of Kylie. The new E! series will follow the star as she juggles her personal life, celebrity persona and cosmetics company.
"These past couple years have been such an incredible journey with the support of my fans," she said in a statement last week. "This show will allow me to give them a peek inside all of the exciting things I am working on."