is staying true to herself.

The singer and  43, launched a new summer line with Walmart under her brand, Jessica Simpson Collection, that showcases her country roots.

“For me, personally, style evolves as I do on a personal level, through each stage of my life,” the designer tells PEOPLE exclusively. “That’s the inspiration for my music right now … [her new album] is an evolution of past, present, future, versatility, femininity, openness and confidence.”

the collection is packed with spring and summer-ready items, from versatile denim pieces to swimwear.

“I’m loving our florals and crochet details for all the spring flings and things!” Simpson says. “The swimsuits and sunnies are for a poolside day with the kids or lunch out with friends.”

She adds, “I wouldn’t miss out on our denim separates. They are staple pieces year round.”     

The collection’s burst of color is also a favorite of Simpson’s. 

“It’s joyful and gives sunny happy vibes,” she says. “I absolutely do dress to boost my mood. When I wear something that feels really good, it lifts my energy, and that’s what I want to give to everyone who wears the JS Collection.”

Aside from the pieces themselves, one of the best parts of bringing the collection to life was snapping photos with her daughter , who appears in the campaign alongside her mom. Simpson wears the ($20), while Birdie wears the 

“Being on set with my Birdie was so special!” Simpson says, before calling the 6-year-old “a little ham.”

“There’s just something magical about seeing my kids in front of the camera. It’s beautiful to witness the confidence and playfulness my kids give in the moment. We had so much fun together,” she adds.

“She loves to be in the center of it all,” the singer continues. “Look out for this little lady, world!”

Their sweet matching moment isn’t unusual for the mother-daughter duo. “It happens pretty often by accident, honestly,” Simpson says. “We seem to coordinate without even trying! I also love a good mommy-and-me look, and it’s so cute when we can make it happen.”

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As for where Simpson turns for style inspiration, she says she has “no rules.”

“Anything from a vintage printed wallpaper in a movie I am watching or a performance piece displayed in an old documentary. Everyone who knows me knows I am observant. I never miss a detail. Inspiration comes at me in visceral ways, every single day. And I honestly don’t know what I would do without Pinterest.”