Jessica Simpson may be less active on the music scene these days, but the singer has been quietly building a fashion empire. Women's Wear Daily reports that Simpson is the face and boss of a nearly $1 billion business.

According to the report, Simpson's lines — which include shoes, accessories, denim, swimwear, watches and fragrances — have seen a combined gross of $750 million in retail sales this year.

So, what's the secret to her success?

"People like her," Vince Camuto, founder and CEO of Camuto Group, the main licensee of her merchandise, said of the recently engaged star. "People look at her as a style icon."

And Simpson shows no signs of slowing down. For fall 2011, the singer is launching a contemporary sportswear line that will include separates and dresses in the $39 to $129 price range; it will be available in more than 650 stores in the U.S. and Canada. The singer explained, "This new sportswear line reflects my evolving style, which combines comfort, femininity and flirty fun."

While Simpson hasn't announced any plans to start designing bridal gowns, she's currently planning her wedding to ex-football player Eric Johnson.

"We have not started planning," Simpson said recently. "I'm trying to get through all this promotion [for my Christmas album]. ... Who knows what will happen?"

Describing the upcoming ceremony as "simple," Simpson added that she wanted to be married by Christmas 2011. "I personally have no idea. I have not set a date and I can't even think about putting together, like, table settings and all that," she said. "We're just going to enjoy the engagement and we'll get married the moment we feel like it."

What do you think of Jessica's fashion empire? Do you swear by her products? Tell us in the comments!