Carrie Underwood's long-awaited bundle of joy is finally here! On Monday, January 21, the country music superstar welcomed another son - Jacob Bryan Fisher - in the "wee hours of the morning". Jacob joins big brother Isaiah, who turns four next month.

In a heartfelt Instagram post shared on Thursday, fans got an intimate look into the first few hours in the lives of the brand new family of four. Underwood shared three adorable photos: one with dad, Mike Fisher, gazing into the camera cradling tiny Jacob, another with the camera turned on herself, holding Jacob skin-to-skin, and a third - Isaiah meeting his baby brother and holding him for the first time (with help from dad!).

"Jacob Bryan Fisher entered the world in the wee hours of the morning on Monday," the caption read. "His mom, dad and big brother couldn’t be happier for God to trust them with taking care of this little miracle! "

Underwood broke the news of her pregnancy last August in a two-minute video posted to Instagram. It had already been quite the year for the star, releasing a new album, and healing - both physically and emotionally. Many fans remember her accident last fall when the singer fell and required over 40 stitches to her face. But she also suffered three devastating miscarriages - leaving her struggling to answer the question of why she was unable to have another child.

"Why on Earth do I keep getting pregnant if I can't have a kid?" she said, recalling those tough months. "Like, what is this? Shut the door. Like, do something. Either shut the door or let me have a kid."

The Cry Pretty songstress has been candid about her struggles to grow her family since giving birth to Isaiah nearly four years ago. In an interview with CBS Sunday Morning this past September shortly after announcing her pregnancy with Jacob, Underwood recalled being afraid to be angry.

"What can I complain about?" she said. "I have an incredible husband, incredible friends, an incredible job, an incredible kid. Can I be mad? No."

Fortunately, Underwood was able to turn her feelings of loss and grief into hope - and through her work, songwriting, touring and performing, she found the courage to keep going. And go she did. In September, Cry Pretty debuted at no. 1 on the Billboard 200, making her the first woman to bring four country albums to the top of the all-genre Billboard 200 chart.

Still, we have a feeling the accomplishment she is most proud of can't be found on a Billboard song list.

"Our hearts are full, our eyes are tired and our lives are forever changed. Life is good," she said.

Congratulations to the whole family!

NEXT: Carrie Underwood Gives Birth: 20 Things To Know About Her And Her Family