Anastasia Soare immigrated to Los Angeles in 1989 to escape the hardships of Romania's Communist government.

She worked as an aesthetician at a salon and quickly realized that no one was paying attention to eyebrows.

She used a mathematical principle, called the golden ratio, as her framework to shape eyebrows based on people's bone structure and natural eyebrow shape.

In 1992, Soare started her own grooming business in Beverly Hills and it became the "best kept secret in Hollywood" to a-listers such as Jennifer Lopez and Naomi Campbell.

Anastasia Beverly Hills has grown into a company with 300 employees and continues to be a favorite among celebrities like Kim Kardashian.

Anastasia Soare was mastering eyebrows long before it was a beauty craze.

The Romania-born CEO and founder of Anastasia Beverly Hills has amassed a fortune by capitalizing on her attention to brows. Forbes estimates her current net worth at about $1 billion, putting her for the first time in her career on its list of the richest self-made women in the US at No. 21.

Her company's product line, launched in 2000, is now available in almost 2,000 stores internationally from Sephora to Nordstrom and is still expanding, according to Soare. Popular items include Dipbrow Pomade and a highlighting pencil that aims to give brows texture and structure. Anastasia Beverly Hills has benefited from intense exposure on social-media platforms like Instagram, where the brand has 17 million followers. Soare even has the approval of Kim Kardashian, who calls her the "eyebrow queen."

"I like to give myself credit for reinventing eyebrows," Soare tells MONEY. "My dream was that every single woman on planet earth should have the opportunity to do eyebrows and fill them in. It organically grew to where we are today."

We talked to Soare about the idea that drove her empire, how it blew up, and her career advice.

Fleeing communism for American opportunity

Anastasia Soare (right) attends a pre-Oscar party in 2010 at Anastasia Beverly Hills with Maria Bravo (left) and Raj Kanodia (center). Jesse Grant/Getty

Soare immigrated to Los Angeles in 1989 to escape the hardships of Romania's Communist government — along with the cold weather. "It was quite difficult to do anything," she explains of her home country. "In winter in the evening, we would have no heat. You would go to bed like you were going skiing. It was very inhuman."

Knowing little English, she worked as an aesthetician at a salon and quickly realized that no one was paying attention to eyebrows. She had a plan, drawing on memories of her mother getting her eyebrows tweezed and the golden ratio she learned while studying art that's used to illustrate pleasing symmetry and proportionality. That mathematical principle is still the underpinning of her work.

"I developed a technique for how to shape eyebrows according to people's bone structure and natural eyebrow shape," she says. "I remember my eyebrows in high school were thin and round because my aesthetician didn't know very well the shape that would create the perfect balance with my face. I looked surprised in all the pictures of me. I needed to understand for myself what was exactly the perfect shape for me."

Mastering eyebrows for Faye Dunaway and Naomi Campbell

Anastasia Soare and beauty blogger, Sananas, attend a launch party in 2016 for an Anastasia Beverly Hills line at Sephora. Julien M. Hekimian/Getty Images for Sephora

She translated that skill for customers. Her boss didn't believe in the concept, so in 1992, she rented a small room in a Beverly Hills salon, where in addition to providing facials and body waxing, she sculpted eyebrows. It became the "best kept secret in Hollywood," Soare says, and her client roster soon included the likes of Faye Dunaway, Jennifer Lopez, and supermodels like Cindy Crawford and Naomi Campbell. By 1997, she had her own salon on Bedford Drive, which she still runs.

"My landlord — he was an interesting character — was like, 'Get out of here. This is Beverly Hills. You can't make money doing eyebrows.' No one believed me," she says. She was proven right when women were waiting three hours to get their eyebrows done at her salon.

A post shared by Anastasia Beverly Hills (@anastasiabeverlyhills) Jun 28, 2018 at 11:52am PDT

Soare concocted her own mix of eye shadow and aloe vera to help define people's look. Observing that "there were no products on the market for eyebrows," she set about filling that gap. When her line was getting off the ground, she traveled to teach customers "how to use powder in your eyebrow like you use lipstick on lips or mascara on lashes."

Over time, they were convinced. Soare credits her adopted country and the helpful, encouraging women who believed in her with Anastasia Beverly Hills' runaway success. "In this country, you have so many opportunities. That's why I worked so hard," she says. "I think coming from another country where you never have opportunities, I saw those. I couldn't believe it. I wanted to sleep three hours a night and work more. You could achieve so much."

Overcoming money problems — and why getting rich isn't everything

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There were other barriers, however. As a new immigrant, Soare needed capital to jumpstart her company. "I didn't have a credit card. Banks weren't throwing cards at you like they are now," she explains. With no credit, she went to Wells Fargo and persuaded a manager to give her a chance. "I said, 'I'm going to be your customer forever and make lots of money. I will keep it in your bank.' I still have a business account with them."

As Anastasia Beverly Hills has grown to 300 employees, the difficulties have shifted. She's now concerned with forming the right teams around the world. "I like to change challenges into great opportunities," she says. "This is how I perceive business. I used to work from the moment I woke up until midnight when I went to bed. I do the same thing now."

While it's taken her to the top of the beauty industry, Soare insists that raking in cash has never been her intention. She has tough advice for anyone who wants to build a venture like her.

"I think they should take it slow and be authentic. You should be passionate," she says, adding that making her customers happy and seeing their positive feedback is the ultimate reward. "If you do it for the money, it never comes out well."