The Important Entrepreneurship Lesson From Jessica Alba and Sarah Michelle Gellar

Jessica Alba and Sarah Michelle Gellar both had successful careers acting on television shows and starring in movies, but now the women spend their time as the founders and creative leaders of startups.

Alba is the chief creative officer of , which creates and sells what it brands as non-toxic goods such as laundry detergent, makeup and baby products and was recently valued at . Gellar is the chief brand officer of , which launched last October with a line of organic baking mixes.

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What do the two women have in common? While raising children, both encountered a problem that no existing business was addressing. Alba sought products that didn't contain potentially harmful chemicals, and Gellar wanted an easy way to bake with her kids using healthy ingredients.

"I really found a need that wasn't being met," Alba said Saturday during Martha Stewart's fifth annual American Made Summit in New York City. "I was just frustrated with government and bureaucracy. I knew I had to create a business that suited my needs."

For Gellar, launching her own business was also a way to spend more time with her children.

"I didn't want to miss a moment," she said at the Summit. "I wanted to control my destiny."

Both of these women's founding stories serve as an important reminder: Before you pursue a business idea, make sure it's something you care about, and that you will offer something unique.

"When you think of starting a company, you can't do a me-too company," Alba said. "Really understand what you're doing that nobody else is doing. Care about the details."

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While both Alba and Gellar admitted that being famous helped them get a head start, both said that they faced challenges as women and because of their celebrity status.

"'Oh, Buffy bakes? Great...'" Gellar joked about reactions to her idea from investors and partners. But she said that she relishes the challenge.

"We are shaking up a $5 billion category that hasn't been touched," she said of the baking ingredients market. "It's a tough road, but man is it satisfying.”