Kylie Jenner is officially the youngest self-made billionaire of all time, snatching the title from Facebook founder Mark Zuckerberg.

Jenner, 21, was finally given the title after months of speculation on Tuesday by Forbes as it unveiled its annual billionaires list.

At 21, she is both the youngest self-made billionaire and the youngest billionaire on Forbes' 'young billionaires' list.

Jenner has amassed a personal net worth of $1billion through her wildly successful range of make-up, Kylie Cosmetics.

Kylie Jenner is officially the youngest self-made billionaire of all time, snatching the title from Facebook founder Mark Zuckerberg

She overtakes Zuckerberg, who was 23 when he made his first billion 11 years ago in 2008.

Now, he is the eighth richest person in the world with a fortune of $62.3billion.

Jenner is the youngest in her famous, reality TV family and the first to hit the billion dollar landmark.

She was surprised by the success of her cosmetics company which was only founded in 2015 but is now worth an estimated $900million.

Jenner, who owns a 100 per cent stake in it, has separate income from endorsements and her family's reality TV show. She also owns an impressive portfolio of real estate.

That's a nice pat on the back Kylie Jenner on becoming the world's youngest self-made billionaire

'I didn’t expect anything. I did not foresee the future. But [the recognition] feels really good.

'That’s a nice pat on the back,' Jenner told Forbes.

She credits her success to her enormous social media following which ensured her customer base before she made her first product.

'It’s the power of social media. I had such a strong reach before I was able to start anything,' she said, adding that she sees the company going 'very far'.

'I see [Kylie Cosmetics] going very far. I work really hard,' she said.

Her mother Kris would not rule out that she may sell the company in the future.

'It’s always something that we’re willing to explore,' she said.

Only two of the star's sisters congratulated her success. Kendall, her closest in age, posted on Twitter and Instagram in support of her whereas Kim tweeted her pride.

Only two of Kylie's famous sisters congratulated her on social media

Jenner was also congratulated by her boyfriend and the father of her child, Travis Scott

Facebook founder Mark Zuckerberg (left) was the youngest self-made billionaire when in 2008 when he was 23. Also on this year's list is Snapchat founder Evan Spiegel (right with his wife Miranda Kerr). At 28, he has a fortune of $2.1billion and is the richest of the young, self-made billionaires

Amazon mogul Jeff Bezos remains the richest man in the world with an estimated fortune of $131billion. When his divorce to his wife MacKenzie is finalized, he will likely be knocked from the top spot

Miss Jenner is able to keep so much of the profits because she has tiny overheads, outsourcing production and employing just seven full-time staff.

As an added bonus in her ultra-competitive family, Miss 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 $350million.

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.’

Amazon mogul Jeff Bezos remains the richest man in the world with an estimated fortune of $131billion.

When his divorce to his wife MacKenzie is finalized, he will likely be knocked from the top spot.

Donald Trump is the 715th richest person in the world with a net worth of $3.1billion

Also on the list of young billionaires is Snapchat founder Evan Spiegel.

At 28, he has amassed a fortune of$2.1billion.

He, Jenner and John Collison, 28, are the only self-made billionaires on the young list this year.

Collison is the founder of the Irish payment company Stripe. He is worth $2.1billion.

Sisters Alexandra and Katharina Andresen, aged 22 and 23, are also on the list.

The Norweigan sisters are heiresses to their father's holding company, Ferd S, and they each now have a personal fortune of $1.4billion.

Seven of the 10 richest people in the world are American. All are men.

The richest woman in the world is Francoise Bettencourt Meyers who, along with her family, has a fortune of $49.3billion. They own a 33 percent stake in L'Oreal.

Donald Trump is the first billionaire president of the United States. He is the 715th richest person in the world with a net worth of $3.1billion.

Tesla founder Elon Musk is the 40th wealthiest person in the world with a net worth of $22.3billion.

However, it wasn’t all good news for the mega-rich, as the combined net worth of this year’s 2,153 billionaires fell from around £6.9trillion ($9.1tn) to £6.6trillion ($8.7tn).

Forbes says there are simply fewer billionaires around than last year as economists fret about a looming global slump.

The list included 52 British entries, led by the Hinduja brothers, Srichand and Gopichand, who control the Hinduja Group conglomerate, with a net worth of £12.9billion ($16.9bn).

Behind them, ranked as the wealthiest single individual in the UK, is Sir Jim Ratcliffe, founder of the chemical company Ineos, and worth £9.2billion ($12.1bn).

With 607 billionaires, the US has more than any other country.