Kylie Jenner, 20, and Kourtney Kardashian, 39, look like TWINS as they promote cosmetic collaboration

Kylie Jenner and Kourtney Kardashian are working together on a cosmetic collaboration. And to plug the new products, which will be released on Tuesday, the beauties posed side by side in white bikinis. 

The 20-year-old Kylie and the 39-year-old Kourtney practically looked like twins.

The 20-year-old mom to baby Stormi was the one who captioned the image with, 'MOMMYS ☺️.. oh and If you didn’t already hear.. we’re COLLABORATING and it drops in 4 DAYS! KOURT X KYLIE @kyliecosmetics.'