Just three months after bringing home his adopted daughter Willa Gray in early May, Thomas Rhett and his wife Lauren have officially welcomed their second child, also a girl. Ada James Akins was born on Saturday (Aug. 12) at 10:28PM; she weighs 7 pounds, 3 ounces.

Rhett and his wife shared the news of baby Ada's birth on Sunday (Aug. 13). In his post on Instagram, Rhett shares that Lauren was in labor for almost 36 hours.

"It was truly the most amazing thing I have ever experienced," he writes. "[Lauren] is by far the strongest human being I have ever met, and I have a new-found respect for moms around the world."

In an Instagram post of her own, Lauren adds, "Only Jesus got me through that" -- but also that Ada "is sooo worth it."

Biological Baby Akins came as a surprise to Rhett and his wife: Lauren realized that she was pregnant shortly after the couple began the process to adopt Willa — even though they had stopped trying to get pregnant.

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“When we began the adoption process, we said, ‘Let’s wait, let’s give this adopted child his or her time with us, and then we’ll continue our family,’” Lauren recalled when she and Rhett announced her pregnancy. So, when the two were in Tanzania in December and Lauren started feeling ill, “I was 100-percent sure I was not pregnant … I was convinced it was food poisoning.”

Family has been, and will likely continue to be, a huge focus for Rhett in terms of his music career, too.

“I’ve written a couple songs that just talk about the severe shock of knowing that you’re adopting a child and then you find out that you’re pregnant,” Rhett said at a recent media event. “I can definitely see myself in the near future pretty much only writing about my children. It will be fun to see how they act and see what kind of inspiration I get from them.”

Despite this massive growth to his family in the last few months, Rhett is still keeping busy in his career, too: He'll release his latest album, appropriately titled Life Changes, on Sept. 8.

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