Kylie Jenner turned her insecurities about her lips into a near billion-dollar business.

In the latest issue of Vogue Australia, the youngest Kardashian sister opened up to older sister Kendall Jenner about how she did it and why she's more secure about her looks today.

"My lip kits started with number one, my obsession with make-up and lips specifically, and just how I took my insecurity with my lips and turned it into my business model," Jenner told her older sister, Kendall. "I just loved bigger lips, and I just got obsessed. To this day, I can't leave the house without lipstick. So, I just think I'm obsessed with doing my make-up and watching tutorials and that's kind of how Kylie Cosmetics started."

Since launching Kylie Cosmetics with her $29 lip kit two years ago, Jenner, who owns 100 percent of the company, has sold more than $630 million worth of makeup, according to Forbes. Last month, Forbes valued Jenner's brand at nearly $800 million. At 20, she is on her way to dethroning Mark Zuckerberg as the youngest self-made billionaire.

Jenner credited the success of her company to her relationship with her fans and great customer service.

"I have a really good relationship with my fans, and I just feel like I was super personal with them, and I let them in to everything. I think they saw that lipstick, for me, was really genuine. So it just worked," she told Vogue Australia.

Today, Jenner is less insecure about her lips. She recently revealed that she is no longer using temporary fillers to enhance her famous pout. In May 2015, she admitted after much speculation that she had enhanced her lips with temporary fillers.

But since having daughter Stormi with rapper Travis Scott in February, Jenner told her sister, "I actually feel like I love myself more after I had Stormi."

Jenner said having a daughter has made her feel like she needs to "accept everything about me."

"Even my ears. I always felt like they stuck out too far, and she [Stormi] has the same ears as me and so now I love my ears," she said. "It's just having a different outlook on life so I can pass that on to her."

Jenner said she and Scott, 26, are learning together as first-time parents. "He's so good with her and she's really obsessed with him," she said.

She also had a message for the couple's doubters: "I just want to say that we never miss a night with each other, we go back and forth from my Calabasas house and the city home that we actually got together."