In the caption of a photo slideshow, Underwood wrote:
"Jacob Bryan Fisher entered the world in the wee hours of the morning on Monday...his mom, dad and big brother couldn’t be happier for God to trust them with taking care of this little miracle! Our hearts are full, our eyes are tired and our lives are forever changed. Life is good."
This is Underwood and Fisher's second child. Underwood gave birth to their first son, Isaiah, in 2015.
The Cry Pretty musician recently opened up about her pregnancy struggles. In September of 2018, she announced her pregnancy with Jacob, while also revealing that she had suffered three miscarriages in the years prior.
"We got pregnant early 2017, and didn't work out...got pregnant again in the spring, and it didn't work out. Got pregnant again, early 2018. Didn't work out," the country music star told CBS Sunday Morning. "So, at that point, it was just kind of like, 'Okay, like, what's the deal? What is all of this?'”
Jacob isn't the only new addition to the Underwood family: Fisher took to Instagram this week to reveal that the family had also brought home a new puppy.
"Meet the newest member of our family! Isaiah affectionately named him Zero. I guess it fits because it’s the chance of surviving if you try to break into our home," joked Fisher on the photo of the adorable pup.
Congrats to the (now very full!) family.