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!

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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."

@jessicasimpson #SS15 #SWIM @nordstrom #fringe #jessicasimpson

A photo posted by Jessica Simpson Collection (@jessicasimpsonstyle) on

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.