The 29-year-old singer took to Instagram Thursday after welcoming a baby boy, Patch Shepherd, with wife Hannah Blackwell Phillips.
Phillips shared a photo of the top of his son's head. He said in the caption that Patch was born Sunday morning.
"Sunday morning our little boy made a fast entrance into the world. I cried more than he did. Hannah was an absolute rockstar in delivery and she has been such an amazing mom these last four days," Phillips wrote.
"I'm forever in love with this little kid," he said.
"He's changed me so much already. We can't take our eyes off of him. He's perfect. Our prayers were answered and this new journey has begun. Welcome, Patch Shepherd Phillips."
Hannah Phillips posted the same picture on her own account.
"Sunday morning, Patch Shepherd Phillips made me a mama. He came ahead of schedule and on his own terms with speed. No amount of reading or listening can prepare one for this kind of love," the new mom said.
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"Phillip has continued to be the most supportive and loving man I know. I knew from the day I met PP that he would be the best daddy," she added. "I don't know how I am going to handle this whole falling in love over and over again daily. Thanks for all the prayers and love."
Phillips and Hannah Phillips had announced in July that they were expecting.
Hannah Phillips gave Phillips a shoutout on Instagram the same month for his support amid her difficult pregnancy.
"We've spent lots of time worried, in pain, or being regulars at the doctor. Not once has this guy complained. In fact, he has just leaned into our love more," Hannah Phillips said of Phillips.
"We have been through more than anyone will ever know in 10 years, but this journey has been such a mental and physical test for me. I fell in love knowing he would be a great dad, but man. What a partner. Y'all get to see the performer, I see a man who sits awake with me all night while I am sick and never misses a beat. The real deal."
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