lauren akins

"We're already kind of in the chaos phase with young kids," the singer explains.

Congrats to the proud parents and their growing girl gang!

Rhett's three daughters have since come around to the idea of a baby sister -- but maybe they'll still get a baby brother one day.

Thomas Rhett shared the news onstage in Texas ... and he also shared the sex of the new baby.

Rhett and Lauren have decided to be forthright about their ups and downs in the hopes that others won't feel alone.

Check out some behind-the-scenes photos before the show airs on Nov. 30.

These two are going to be very busy!

It's beginning to look a lot like Christmas ...

Happy Anniversary to these two lovebirds!

It's an almost unbelievable rustic retreat.