Kourtney Kardashian Strikes a Birthday Pose with Sister Kylie

08/31/2017 03:47 pm EDT

Having just celebrated her little sister Kylie's birthday, Kourtney Kardashian shared a photograph to Instagram of the two of them striking a pose outside in the beautiful sunlight.

In the photo, Kardashian is wearing a purple outfit, comprised of dress pants and a strapped tube-top. Jenner is wearing a white form-fitting bodysuit with a pair of high heels.

In a caption on the photo, Kardashian wrote, "Happy birthday baby sister! Tinkerbell sleep shirts for life. I love you my lip kit queen."

Jenner had quite the birthday celebration this week with family, friends and new beau, Travis Scott. But if you think she was planning to drink the night away to ring in the celebratory milestone, think again. In a new interview, the Life of Kylie star says she's "never had a drink before."

According to E! News, Jenner was asked what she's most looking forward to being in her twenties and she responded, "Probably turning 21. I feel like that's fun. You know, I've never had a drink before so I just wanna know what it's like."

Interestingly, back in 2013, rumors swirled that Jenner and her sister Kendall had been illegally drinking in a 21-and-over nightclub. Their mother, Kris Jenner, quickly fired back that the girls "don't have fake IDs and they don't drink."

"I'm sorry to disappoint, but Kendall & I will not grow up to be let downs. I know that's what some people would unfortunately like to see...but I'm not going to sit around and let grown adults create untrue stories about me underage drinking [and] partying every night with a fake I.D," Jenner tweeted.

Disclosure: PopCulture. is owned by Paramount. Sign up for Paramount+ by clicking here.