Whether donning a sexy, ultrafeminine red-carpet frock or a breezy boho weekend ensemble accessorized with her signature shades and an oversize bag, Jessica Simpson always turns heads with her playful, all-American style. In fact, as we recently noted, the star's fashion empire is estimated at almost a billion dollars.

In honor of Simpson's 31st birthday this weekend, we've rounded up some of her most memorable looks, from her "I Wanna Love You Forever" days in the late '90s, through the "Newlyweds" era, to the present.

And don't miss the 10 reasons why we love Jessica Simpson in the video below: