Not yet 20 years old, this Norwegian teen has become the world's youngest billionaire. 

Tobacco heiress Alexandra Andresen was added to the 2016 World’s Billionaires thanks to her stake in the investment company Ferd, Forbes reports.

Andresen's worth is an estimated $1.2 billion.

The teen horse enthusiast and her older sister, who is 20, each own 42.2 percent of the private company, which their great-great-great grandfather, Johan Henrik Andresen, purchased. It would become Norway's biggest cigarette maker.

The sisters, who rank as the 1,475th wealthiest people in the world, say they've become quite popular thanks in part to their vivid social media presence.

Alexandra's sister Katharina told Norwegian media she's received hundreds of Facebook friend requests since details of their wealth became public.

Despite her great wealth, the Amsterdam University College student posted in September a photo of her tiny dorm room in Holland.

Katharina's Facebook, meanwhile, conveys the elder sister's love of fashion, friends and dogs.

But with all their money also comes the responsibility of keeping a major company up and running. 

As they do in their personal lives, the sisters sound intent of doing business with grace and style.

In a statement on the Ferd website translanted from Norwegian, Alexandra wrote:

"I feel a great responsibility. In a way I think that I have not made ​​me deserving of this, while I want to help develop Ferd and make it even better. Finding a way to give something back, I think is difficult."