Kourtney Kardashian Finally Announces Her New App Is Ready -- Find Out When It Will Launch!

Just in time for the holidays, Kourtney Kardashian is giving her fans a gift -- access to her app!

While all four of her sisters debuted their own mobile apps and websites at the Apple store in New York City in September, Kourtney did not. Many Keeping Up With the Kardashian fans wondered why she was the only Kardashian-Jenner gal who apparently chose not to launch one.

WATCH: Kim Kardashian Shares Pregnancy Secrets & Style Tips on Lifestyle App

On Friday, user @selfishwithlove tweeted the 36-year-old reality star, asking, "@kourtneykardash I have a question, why didn't you launch a website/ app along with your other sisters?" Kourtney replied, writing, "It will launch in December!"

FINALLY.

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Back in September, Kourtney's mother, Kris Jenner, revealed exclusively to ET that the reason Kourtney's was missing was not because she didn't want one, but because it simply wasn't ready yet.

"The girls have been working around the clock for a year on their apps and sites, and Kourtney gave birth to Reign in December," she explained. "While everyone else was deep in production, she was taking time with her infant, nursing and caring for her children. So, she's a little behind, but, it is going to be fabulous."

Kourtney teased her app a day earlier, revealing how her content would differ from her sisters.

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"Mine is more curated," Kourtney said. "I'm obsessed with interior design, so it's a lot about that. I'm obsessed with being a mom. I have very specific ways of being a mom, as well."

"All my friends come to me with mom questions, so just sharing my favorite things," she continued. "There's not one thing on [my app] that I'm not obsessed with thoroughly."

WATCH: Kris Jenner Talks Kourtney Kardashian's Mobile App

ET also caught up with Kourtney's youngest sister, Kylie Jenner, at the Vera Wang NYFW Show, where she gushed over Kourtney's app.

“[It's] going to be amazing," she said. "She loves being a mom. She spent a little more time on it."

To hear more on her sister's family of lifestyle apps, watch the video below.