Country music star Thomas Rhett has become a father-of-four.

The singer revealed on Instagram on Wednesday that he and his wife Lauren had welcomed their fourth daughter, named Lillie, into the world on Monday.

"Lillie Carolina Akins (heart eye emoji) born November 15th. 7.5 pounds of pure joy @laur_akins you are my hero. Watching a child being born is legit a miracle. 4 under 6 here we go!" Thomas wrote alongside a snap of him leaning down by Lauren as she lays with Lillie on her chest in the hospital bed.

Lauren shared a photo of her kissing Lillie on Instagram and added, "Our little miss Lillie Carolina Akins was born on November 15th and our family couldn’t be more over the moon about our littlest joy."

The 31-year-old attended the Country Music Association (CMA) Awards last week and admitted to Entertainment Tonight on the red carpet that his child could arrive at any moment.

"Literally, I'm just waiting on a phone call," he said. "It literally could happen tonight, it could happen tomorrow, who knows? So we're just gonna keep going until we have to go to the hospital."

Thomas and Lauren, who wed in 2012, are already parents to biological daughters Lennon, 21 months, and four-year-old Ada, who was born shortly after the couple adopted now-six-year-old Willa from Uganda.