Baker Ivey Childers has known Christian country singer Carrie Underwood for several years already. And now that Childers is about to expect a baby of her own, she got the sweetest surprise from her best friend—a baby shower.

"We've been friends for gosh, seven or eight years now," Childers told CMT, speaking of Underwood. "We got married a year apart, we're having babies a year apart. We've kind of experience all the milestones in life together. She's most definitely my very best friend."

The two first met when Childers began dating Underwood's music director and bass player Mark. But even before then, the girls already had a connection. Right after Underwood won "American Idol," Childers was hired to bake her birthday cake.

What amazes Childers about Underwood is that no matter how difficult her professional or personal life might get, she never lets anything affect her role as a mom to Isaiah Michael Fisher.

"I watch her, and I'm amazed at what she can handle and how she's not rattled," Childers said. "She calms me. Watching her embrace motherhood the way she has makes me a relaxed person. We're a good balance for each other in the sense that she's very calm and collected."

Given her grounded approach to motherhood, it comes as no surprise how amazing Underwood is at giving advice.

"She's just such a natural," gushed Childers. "She's always been the most excited for me because she's such a loving and loyal friend. She's told me to go easy on myself. Don't be too hard on yourself in everything that you experience with it all. There's gonna be some hard moments, but just remember to not be so hard on yourself. That's the thing I keep hearing from her."