Inside Jordin Sparks and Dana Isaiah's Spur-of-the-Moment Wedding in the Hawaiian Ocean

Jordin Sparks and Dana Isaiah insisted on living separately until they tied the knot, but their wedding ceremony was anything but traditional.

While vacationing in Hawaii with their best friends in mid-July, the American Idol winner, 27, and Isaiah, 25, decided to elope days into their trip.

“We hadn’t had a set plan or anything. We were like, ‘If it happens, it happens. If it doesn’t, that’s okay too,” Sparks tells PEOPLE exclusively about their July 16 wedding day.

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As the couple were walking “up and down the beach,” Sparks saw a paparazzo taking photos of them, and “I looked at Dana and I go, ‘Smile, you’re on camera.'”

After the couple — who are expecting their first child in late spring — headed into the ocean with their friends, the photographer continued snapping away, and that’s when Sparks was moved to become husband and wife.

“We all get in the water and we’re having a good time and I just was like ‘Morgan,'” she says about her best friend. “She had gotten ordained before the trip. I was like, ‘Morgan, why don’t you do it right now?’ And she was like ‘Okay!'”

“I was like ‘Jermaine! Tim! Come on!” adds Isaiah — an aspiring model from Dallas — about rounding up his own best friends. “We did it and then she was like ‘Kiss me!'”

For all the details on Jordin Sparks’ surprise wedding and pregnancy, pick up the latest issue of PEOPLE, on newsstands Friday.

The paparazzo had no idea he had just documented the happiest moment of their lives thus far, and days later photos of the ceremony hit the internet.

“That is basically the picture of the actual moment,” says Sparks, who was wearing a two-piece swimsuit and had a Fred the Flamingo floaty around her waist. “It was so much fun and we had such a great time. I do big events all the time, so to be able to have this moment, it was really special to me in that way. Everybody’s love story is different.”

• with additional reporting by JEFF NELSON