Thompson Square's Keifer Thompson says his wife, Shawna, underwent an almost total transformation after the birth of their son, and he couldn't be happier about it.

Asked to share a few things that surprised him about his wife of nearly 19 years after their son, Cooper, was born in 2016, the singer and songwriter was quick to describe how she matured in the most beautiful way. They started dating as young 20-somethings, new to Nashville, and he viewed them as kids.

"I saw a girl turn into a woman overnight," he tells Taste of Country. "I saw a person who was very dependent upon me become super independent. And I saw someone who was scared to death to have kids take it all on, all on her shoulders. It was powerful.”

Shawna sits next to him, nodding as he describes their individual roles in their marriage up until the point Cooper was born. Keifer took care of stressful phone calls and financial matters — they were both happier when she wasn't burdened. With their son, she doesn't give a second thought to leading during difficult moments as a new parent.

“You know you love someone unconditionally when they fall and cry and you could walk through a brick wall to get to him," Keifer says, speaking of Shawna's love for their son. "You’re just like this animal, this protective animal about this kid and it’s just been really cool to see the transformation."

"Masterpiece," the title track of the duo's next album (June 1), was written about Cooper."

"I started thinking about the definition of masterpiece being an artist's best work,” Keifer says, "Something you’re never going to beat. The best thing you’ll do. For me, that was Cooper. I could win every award there ever was and it's never going to beat this."

Written mostly on their back porch with just a guitar, "Masterpiece" was loosely recorded when Keifer sang it for Shawna. Listen close and you can hear her sniffling through tears on the work tape. Shawna says it's the best song Keifer has ever written, which is high praise.

"I write songs to impress her," Keifer says, laughing but not joking. "If I can impress her, then I’m doing something."

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