"I already love you so much and I can't wait to watch you and your sister become best friends," the country star captioned a photo of the newborn

Brett Young Pregnancy Announcement
Credit: Seth Kupersmith

Brett Young's baby girl has arrived!

The country singer, 40, and his wife Taylor, 33, welcomed their second daughter, Rowan Marie Young, on Wednesday, July 21, they announced Saturday evening on Instagram.

Born in Nashville, baby Rowan weighed in at 8 lbs., 5 oz. and measured 21 inches long.

The pair are also parents to daughter Presley Elizabeth, who turns 2 in October.

"Rowan Marie Young. 7-21-21. I thought my heart was maxed out. I usually don't like to be wrong…… I was wrong. And I can't wait to thank you properly for the opportunity to be your daddy. I already love you so much and I can't wait to watch you and your sister become best friends," he captioned a photo of the newborn.

"FYI….. the women in your life are superheroes and you're the luckiest lady alive. Presley has been begging for you. Be prepared for me to mess everything up and your mom and sister to always be there to fix it. I love you. Welcome to the 'Youngs'"

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Taylor shared the same photo, writing. "Best early birthday present I could possibly ask for! Rowan Marie Young arrived on 7/21/21 weighing 8.5 and 21 inches long. We've been soaking in all of the loves and cuddles from both of our girls and living in a newborn baby bubble bliss. Our hearts could burst. Being a family of 4 is such an incredible feeling. I cannot wait to continue to get to know our sweet girl. We've got one that has daddy's coloring and one that has mama's. Our sugar and spice. We are so blessed."

Young revealed the couple's pregnancy news exclusively with PEOPLE in January, saying at the time, "We really wanted them to be close enough in age so they could have a lot of things in common and be best friends. Tay had her sister close in age growing up, so we both felt strongly we wanted Presley to have the same."

"Tay is so close with her sister, and that's something we always knew we wanted for Presley. We feel very blessed," he added.

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The "Not Yet" singer said they were "so excited" for their new addition, adding that his wife had been a "rockstar" through increased morning sickness this time around: "Unfortunately the morning sickness is real this time, which is unlike the first pregnancy. That being said, everyone is healthy and that's all that matters."

In March, he revealed that he was expecting another baby girl during an appearance on The Kelly Clarkson Show.

For Mother's Day, Young praised his wife on Instagram, writing alongside a family photo, "I would promise to spend the rest of my life telling our kids how lucky they are to have you as a mom. But I don't have to. There's no way that they don't already know. You were born for this job and you do it with such beauty and grace I feel lucky to witness it. Happy Mother's Day pretty girl."

Young's upcoming children's book Love You, Little Lady, based on the lyrics of his No. 1 hit "Lady," will be released Aug. 24.