Ciara Says Kids Future, 9, and Sienna, 6, Were ‘Rock Stars’ While Shooting New Campaign (Exclusive)

Ciara has some fashionable little ones on her hands.

Speaking with PEOPLE about the face of Gap and LoveShackFancy’s new collection, the Grammy winner, 37, celebrated being part of the "beautiful collaboration" with daughter Sienna Princess, 6, and son Future Zahir, 9, who also pose in pieces from the collection.

"This was so, so much fun. They were rock stars. It was a dream," she tells PEOPLE. "I really feel like the pieces I wore are very timeless pieces that merge Gap's iconic styles with LoveShackFancy's vintage-inspired florals and feminine silhouette," the self-proclaimed "tomboy" adds.

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Ciara says her two older kids were "so excited" to be part of the campaign.

"We went to Janet Jackson's concert before the shoot and so it was just a full-on experience. They were super pumped and looked so amazing in the photos."

"Future wore the floral hoodie and classic jeans and he was very, very comfortable in that look," she says, noting that he's getting "very particular about his details."

"Sienna loved this big massive skirt that I had that we both wore together. She really loved that one because she felt like a true princess. It was super dramatic, but also girly."

"Sisi's a bit more girly [than me], but she has a tomboy element to her too so she was fully in her element. And with the combat boots, it had that edge there. She was sassy SiSi when she turned that corner with that skirt on," she laughs. "She was like, 'Let's go!'"

While her youngest, 3-year-old son Win, "is just starting to try to dress himself, which is really cute," the mom is loving watching "that side of their personality evolve and come out" in all three of her kids.

"I will say Future —when you're 9 years old, you're way more aware — I feel like he's really tapping into his inner personality. He’s very, very, very clear on what his vision is," the proud mom shares.

"He's very funny about how his hair is styled, like ‘Mom, I want the twists this week. I want these braids,’ like, ‘No, it needs to be like this, like, I'm going to wear my durag. I keep my bracelet nice and neat and a certain way.'  He's in that phase where they start to really be super aware and in tune with that side of himself."

They share some style points but with SiSi "she's fearless and a bit rough, like Mommy, but has a bit of a softer touch."

"I look at her and I see so much of me in her. It's so sweet to see them tapping into their own fashion style and sense and waking up and getting themselves stressed on their own and picking their own looks," she continues. And just being very confident in their fashion choices, I love that, to see that side of their personality evolve and come out."

The family is ready to share this collection with the world, with the singer raving, "I can't wait for my fans to see it."

"I think that people are going to appreciate this collaboration and what the fashion choices are and the pieces that they get as part of it. I'm excited for the campaign to finally be out after the fun of being part of it. The time is finally here."

Ciara's collection will be available to shop at select Gap and LoveShackFancy stores (and online) starting Aug. 4 and prices range from $13 to $248.

For more on Ciara and her family, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribe here.