Image copyright Getty Images Image caption The reality television star is set to hit the milestone earlier than Facebook's Mark Zuckerberg

Keeping Up with the Kardashians star Kylie Jenner is worth $900m (£680m) at just 20 years of age, says Forbes.

The business magazine said the social media star is on track to become "the youngest-ever self-made billionaire".

The fashion guru, the youngest of the Kardashian clan, started selling her own cosmetics three years ago.

Her most famous sibling, Kim Kardashian West, 37, has a notably lower net worth of $350m.

Ms Jenner, who is still currently not old enough even to legally drink alcohol in the US, will turn 21 in August as her Forbes cover edition hits newsstands.

"What her half-sister Kim Kardashian West did for booty, Jenner has done for full lips," Forbes writes, describing her famous pout.

Earlier this week Ms Jenner, a mother of one daughter named Stormi, announced she would stop receiving lip injections, known as dermal fillers.

Image copyright Reuters Image caption The influential beauty mogul has more than 110m followers on Instagram

She admitted during an episode of Keeping Up With The Kardashians in 2015 that her natural lips had been "an insecurity" that she wanted to change with temporary lip fillers.

She later launched her brand Kylie Cosmetics, which included a line of lip products designed to help customers make their lips look bigger through over-lining and filling.

Unlike those of traditional cosmetic brands, her products are almost exclusively sold online.

Her cosmetics have proven exceptionally popular with fans, selling out almost instantly at every website re-stock and leading to server crashes.

Ms Jenner's company, which she wholly owns, is worth $800m, according to Forbes.

She is number 27 on Forbes' list of richest self-made women in America, leap-frogging Barbra Streisand ($400m), Beyonce Knowles ($335m) and Taylor Swift ($320m).

Ms Jenner is on track to become a billionaire earlier than Mark Zuckerberg, the founder of Facebook, who achieved that status at age 23.

Evan Spiegel, the owner of Snapchat, also became a billionaire in his early 20s, but it is unclear exactly when he met that goal.

"wow. i can't believe I'm posting my very own @forbes cover," she wrote to her 110m Instagram followers on Wednesday.

"thank you for this article and the recognition. I'm so blessed to do what i love everyday. i couldn't have dreamt this up!"

Dictionary.com tweeted a definition, seemingly directed at the Forbes piece, that "self-made means having succeeded in life unaided".

Ms Jenner first rose to fame at the age of 10 when she appeared with her family on their eponymous reality show.

On social media, some users scoffed at Forbes' use of the term "self-made", pointing out that Ms Jenner's parents were already wealthy and famous.

You may also like: