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It's been a banner year for Jessica Simpson: the billion-dollar business mogul became a new mom for the first time, and now she's on ET's Power List!

Pics: Jessica Simpson's Amazing Weight-Loss Transformation

Jessica has 5.7 million Twitter followers and her Weight Watchers deal is worth a reported $4 million. But it's her billion-dollar retail empire that's truly stunning: The Jessica Simpson Collection is valued at some $400 million, and her fragrance line alone is worth some $50 million.

So when did Jessica first know she was truly famous? "It was 2003 -- I was in Boston for a wedding book signing and there were 7,000 people that showed up, and I couldn't even get out of the car because it was like a hazard," she says, "but people where banging on the car, and I felt like a Beatle."

Related: Jessica Simpson Welcomes Baby Girl

Check out the video to see Jessica take the ET Power List Quiz: What's her best advice? What's her proudest moment? Watch to find out…