Morgane shared the news on her Instagram on Wednesday, May 29, posting a black and white photo of her son swaddled in a blanket and lying in the hospital, a piece of paper with his tiny footprints resting behind him.
"Sweet boy... It’s hard believe almost a month has already gone by," she wrote. "Time flies faster than I ever thought imaginable. My heart is so full!"
Fans and friends offered congratulations and well-wishes to the family, including Rita Wilson, who commented, "It all goes too fast."
"Wow Morgane!! Beautiful," wrote Lucie Silvas, while Little Big Town's Karen Fairchild posted four red heart emojis.
Morgane originally announced the baby's birth on Sunday, May 12, sharing an Instagram photo of her hand resting on the infant's tiny stomach.
"The most perfect Mother’s day...I wish all you Mama’s the happiest of days today!" her caption read.
The 36-year-old previously gave birth to twins in April 2018, with her husband announcing that the couple was expecting again during a show at Madison Square Garden in New York City in November.
“I've got an announcement to make," Stapleton told the crowd. "Some of you may know that we have four children. We just had twins about seven months ago. Now there’s four for us, but we’re gonna make it five!”
In addition to the twins, the Stapletons also have a son and a daughter. The couple, who married in 2007, has not publicly revealed the names of their children.
The twins' birth was originally announced last year during the ACM Awards by Reba McEntire, who spilled the beans on stage during the broadcast. Judging by his tweet after the fact, the musician wasn't too upset, with Stapleton retweeting a video of McEntire making the announcement and thanking her for sharing his family's good news.
Stapleton has previously opened up about his and Morgane's decision to keep their children's information private, explaining that he wants to allow them to make that choice for themselves.
"I signed up for this," he said backstage during CMA Fest in 2018, via The Boot. "My children did not. I am a very private person, and in that respect, I keep my children out of it. They're children, and they deserve the chance to be children."0comments
"My wife comes out [in the public eye], and she's an adult, so she can choose to do that," he added. "My children did not make that choice, and [talking about them in detail in public] is, for me, kind of off limits."
Photo Credit: Getty / Lester Cohen