Kylie Jenner has left Facebook founder Mark Zuckerberg in her dust.
At 21, Kylie Jenner has become the world's youngest self-made billionaire - stealing the title from the less glamorous technology guru.
Earlier this week, Jenner, a reality TV star and cosmetics entrepreneur, was named the 'youngest self-made billionaire of all time' in Forbes's annual ranking of the world's richest people.
The 21-year-old social media sensation is the youngest member of the Kardashian-Jenner clan, made famous by the long-running US reality show Keeping Up With The Kardashians.
The business magazine conceded she was also the first 'selfie' billionaire, as the success of her three-year-old make-up range is largely founded on Jenner's extraordinary popularity on social media.
But social media wunderkind Zuckerberg - who didn't become a billionaire until he was 23 - saw his place slip in the Forbes list, with his personal wealth shrinking by US$8.7 billion ($12.8b) in the past year on the back of Facebook's declining fortunes and a rash of privacy scandals.
Amazon founder Jeff Bezos remained at the top of the list, widening his lead over second placed Bill Gates as his wealth soared to US$131 billion ($193b), up US$19b ($28b) in the past 12 months.
However, it wasn't all good news for the mega-rich, as the combined net worth of this year's 2153 billionaires fell from around US$9.1 trillion to US$8.7 trillion.
Forbes says there are simply fewer billionaires around than last year as economists fret about a looming global slump.
Forbes says Kylie Jenner's make-up business - which she owns outright - is worth US$900 million ($1.3b), accounting for almost all of her US$1 billion valuation. Last year, Kylie Cosmetics racked up around US$360 million ($532m) in sales.
Jenner set the brand up in November 2015 when she started selling hugely popular 'lip kits' that included liquid lipstick and matching lip-liner. She then expanded her range to include blusher, highlighter, concealers and eyeshadow.
Jenner is able to keep so much of the profits because she has tiny overheads, outsourcing production and employing just seven full-time staff.
She trademarked the phrase "Kylie Lip Kits … for the perfect pout" two years before setting up her company with US$250,000 ($370,000) of money she had made through modelling and reality TV work, the Guardian reported.
"Ever since I was probably 15 I've been obsessed with lipstick. I could never find a lip liner and a lipstick that were the perfect match. So that's where I thought of the idea that I wanted to create my own product," Jenner said.
Jenner said she was scared that sales might not take off when the website first launched. "I kept calling my mother, saying: 'Mom, I'm so scared. Do you think it's going to sell?' Because I put all my money upfront. You know, it's all my money. I put everything into this."
As an added bonus in her ultra-competitive family, Jenner is now estimated to be worth almost three times as much as her more famous sister Kim Kardashian West.
The latter also has a make-up business but has to scrape by with a net worth Forbes puts at US$350 million ($517m).
Along with the rest of their photogenic family, the sisters have worked tirelessly to monetise their fame despite critics complaining they are simply famous for being famous.
The family matriarch Kris Jenner has kept a shrewd eye over her six children's burgeoning fortunes, as well as their public relations. She charges a 10 per cent management fee from all of them.
Kylie, who has a daughter with her rapper boyfriend Travis Scott, claimed she never expected to become so rich.
"I didn't expect anything. I did not foresee the future," she told Forbes.
"But [the recognition] feels really good. That's a nice pat on the back."