Mila was born at Jennie Stuart Medical Center in Hopkinsville, Kentucky, weighing 6 lbs., 12 oz., and measuring 19 inches.
"Ashley and I are over the moon about being able to start a family. We have been anxiously waiting for this day to come," Reynolds told ET exclusively. "And wow, she is beautiful. I never in a million years thought becoming a father would affect me the way that it has."
"This little girl has stolen my heart already, and it’s only Day 1. I can only imagine the joy she will bring us over the next several years," he added.
Reynolds and Jay tied the knot in May 2016 and announced that they were expecting in April. Jay is also the mother to a 6-year-old daughter, Kylie, from a previous relationship.
Following the arrival of Mila, Reynolds took to Instagram to share a sweet family pic.
"I officially am a Dad to the most beautiful little girl. Mila Rose Reynolds was born today weighing in at 6 pounds 12 ounces. ❤️ #born #baby #newborn #delivery #mila #rose #babygirl #daddysgirl #littlebaby," he wrote.
"She stole my ❤️ at hello!," he captioned another pic of himself lying down with Mila on his chest.