Wes and Katy Hansen got the surprise of a lifetime this summer.

Wes and  Katy Hansen are your typical married couple.

Wes, 33, owns a pool construction company and Katy, 30, works in sales.

They’re expecting their first child in December and enjoying the simple things before they become a family of three.

This summer, they attended a Garth Brooks concert in Los Angeles – and the experience was anything but ordinary.

The day before the show, Katy had a gender ultrasound to determine the baby’s sex.

“We had a random joking moment,” Wes says, “where we said, ‘How cool would it be if we could get Garth to reveal the gender at the concert,’ never  thinking it would possibly happen.”

Well … it happened.

“When I brought it up, my wife got all excited and made a sign,” he says. “But then we got into the venue, and Katy said, ‘Let’s just open the envelope (with the baby’s gender), I wanna see it, this isn’t ever going to happen.’ ”

But then, the roles were reversed.

“At first, I was the pessimistic one,” Wes explains. “I was initially telling her not to get her hopes up. But when we got to the show, I wound up holding the sign, and putting it up throughout the concert, hoping Garth would see it. When he came to our side, sure as hell, he happened to see it.”

Before closing his concerts, Garth does “housekeeping,” during which he comes out on stage, looks at signs throughout the crowd and takes song requests.

Wes and Katy’s bright yellow sign caught his eye.

 It read, “Working on a full house – Girl? Boy?” 

And that’s when the once-in-a-lifetime moment happened for the couple.

“I saw this sign earlier tonight,” Garth said to the crowd. “I don’t think it’s a song request … I’ve been trying to figure it out all night.”

He pulled Katy and Wes to the side of the stage, took the envelope from Katy and said, according to Wes, “I’m so excited for you because I have three of these … and they mean everything to me.”

That’s when the lights inside the venue all  turned pink.

“When he said that,” Wes recalls, “we knew it was a girl because Garth has three daughters.”

Garth then promised to pay for the baby’s college…