Jessica Simpson Flaunts Slimmed Down Bod in New Swimsuit Campaign

Jess looked smokin' hot in the Arizona heat!

We don't know what's hotter -- the Arizona heat or Jessica Simpson!

The singer-turned-fashion designer flaunted her curves in a black fringed one-piece from her eponymous line's new bathing suit collection.

The Jessica Simpson Collection’s spring-summer 2015 line was appropriately named "Sedona." "I’ve always been inspired by the Southwest," Jess wrote on her website. "For our Spring 2015 campaign, my team and I packed our bags and hit the dusty trail, travelling [sp] eight hours -- by tour bus -- from Los Angeles to Sedona, Arizona."

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Jessica continued that "the adventure is in the journey," but can you picture this fashionista on a tour bus? Nope, neither can we!

She wasn't kidding about the dusty trail though -- her crew got to the photo shoot site by Pink Jeep Tour’s off-road SUVs. Check out behind-the-scenes footage here:

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The 34-year-old looks like she was born with the modeling gene, as does her equally genetically-blessed daughter Maxwell. Jess recently Instagrammed a pic to celebrate her little girl's birthday. "May 1 my Maxi Drew turned 3…." the proud mom wrote. "I am in complete denial."

With her well-documented weight struggles -- both before and after having her daughter and 22-month-old son Ace -- it's nice to see Jessica as comfortable in her own skin as ever.

Although Jess loved showing off her pregnant bathing suit bod too, as evidence by this pic she posted on Twitter while pregnant with Ace in December 2012:

Hubby Eric Johnson knows Jess has looked good at any size. Hear what the former NFL star had to say about his wife in the video below.