She teased the venture on Tuesday (18Apr17) with a moody Instagram video featuring the siblings, naked from the shoulders up, looking almost identical with dead straight, centre-parted hair.
The video ended with the caption: "KKW x KYLIE COMING SOON", and Kylie added: "COMING SOON @kyliecosmetics #KKW".
A post shared by Kim Kardashian West (@kimkardashian) on
The promo had already been viewed almost three-and-a-half million times at press time.
Both sisters apply lipgloss during the video - Kim's pale and matt, Kylie's slightly darker and glossy - suggesting new lip kits are certain to be part of the collaboration. Kim also films herself with her phone.
Kylie, meanwhile, is revealing a little more about another important part of her beauty routine - her nails. In a chat with Fashionista founder Faran Krentcil for Elle magazine, the young star admits the secret to maintaining her long nails is weekly tough-ups.
"Part of it is making sure they’re done correctly," she says. "I get them done once a week, which isn’t normal."
Her sister Kendall goes on to explain that their mum Kris Jenner was very particular about her youngest girls' nail care when they were growing up.
"My mom would make us do it," she explains, "She would have a nail artist come to the house once a week and she would make us get our nails done. She was like, 'You are never going to look like you’re not put together'."
Only one of the sisters has kept up the intense routine.
"Now I only do them on (a photo shoot) set, to be honest," laughs Kendall, "but Kylie..."
"I took her (Kris') advice," her sister smiles.
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