KYLIE Jenner and Kourtney Kardashian have made the latter’s birthday one to remember.

baKourtney Kardashian celebrated her 39th birthday on Wednesday, and the occasion was marked with a never-ending string of tributes from friends, family and fans.

bbNow, new mum and sister Kylie Jenner has decided to use the big day to announce she will be collaborating with the b’day girl for her latest cosmetics line.

buKOURT X KYLIE is a new collection, with three eyeshadows and three lip kits.

bnTaking to the official Kylie Jenner Instagram and website, the 20-year-old shared a red hot promo image.

asKylie and Kourtney looked sensational as they both stunned in nude lingerie, with Kylie showcasing her famous rear in the disappearing thong outfit.

Kourtney reclined on her back, running her hand through her hair and proudly flaunted her washboard stomach in the cut-out one-piece.

Writing to her 107 million followers, Kylie captioned the image: “HAPPY BIRTHDAY TO THE QUEEN!

“So excited to announce the KOURT X KYLIE collaboration.”

It would appear their fans are just as keen, as the post has now been liked 3.3 million times.

The announcement comes as the Kardashian family are once again at the centre of headlines.

This time, it’s because Khloe Kardashian has just given birth to her first child, a daughter named True.

True was born in the midst of a cheating scandal surrounding Khloe’s partner Tristan Thompson.

Kylie used the moment to unveil the latest addition to her hugely successful cosmetics line.

In June last year, Kylie also collaborated with Khloe for two new cosmetic sets, called the KoKo collection.

The starlet launched her Kylie Lip Kits back in 2015.