Mark Zuckerberg, who previously held the title, was 23 when he became a billionaire.
While Forbes revealed last year that Kylie was on track to become a billionaire, they've confirmed she has now crossed the threshold thanks to signing an exclusive distribution deal with the beauty retailer Ulta, which placed her Kylie Cosmetics products in 1000 stores across the US.
Within just six weeks of signing the deal, Kylie Cosmetics sold an estimated $54.5 million worth of products in Ulta stores. Thanks to the expansion, Kylie Cosmetics' revenue climbed 9% last year to an estimated $360 million.
Forbes now estimates that the company, which launched in 2015 and is owned in its entirety by Kylie, is worth $900 million.
Kylie credits the historic achievement to "the power of social media," adding that while she never expected the accolade, it's a "nice pat on the back."
In fact, just last month Kylie defended her "self-made" status, acknowledging that while her fame gave her a "huge platform," none of her money is inherited.
Speaking to Paper, Kylie said: "I had such a huge platform, I had so many followers already and I had so many people watching me. But my parents told me I needed to make my own money at age 15 — that it was time to learn how to save and spend my own money. What I'm trying to say is, I did have a platform but none of my money is inherited." SHARE THIS STORY USING ANY OF THE BUTTON BELOW ⬇ PLACE YOUR TEXT ADVERT BELOW ⬇⬇⬇