Mark Zuckerberg's record as the youngest billionaire has been beaten by the reality TV star

At the age of just 21, Kylie Jenner has officially entered the billionaires' club thanks to her make-up business, work in reality TV and modelling, and from having grown up in one of America's richest families. Forbes' latest rich list has described Jenner as the youngest ever self-made billionaire, as she is two years younger than when Facebook founder Mark Zuckerberg passed that threshold. Of course, there is some dispute over whether she is truly self-made but the statistics surrounding her make-up brand are truly staggering. Founded three years ago, Kylie Cosmetics is already estimated to be worth $900 million alone with $360m of revenue last year - and all profits go straight to its owner. Much of the work is outsourced, such as to manufacturer Seed Beauty and retailer Shopify, but Jenner's social media fiefdom has supplied an endless demand for the products. The wealth accumulated by the daughter of Kris and Caitlyn Jenner and half-sister of the Kardashian clan still pales in comparison to the world's richest man. Forbes reckons Amazon founder Jeff Bezos is now worth $131 billion, $19bn more than last year. Microsoft founder Bill Gates, who has given away a reported $35.8bn of his fortune to his charity initiatives, is second on $96.5bn while L'Oreal heiress and chairwoman Francoise Bettencourt Meyers is the richest woman thanks to her $49.3bn wealth.