"Congratulations Derek and @hannahbjeter on the birth of your baby girl, Bella Raine Jeter, born Thursday, August 17," the tweet read.
The former MLB star and model tied the knot in July 2016, and Hannah announced her pregnancy in a post on The Player's Tribune in February.
"Now, pregnant with our first child, Derek and I are looking to the future," she penned. "He already has a name in mind—he's set on it. (We'll see.) He'll say when he calls me during the day: 'So, how are you and so-and-so doing?' 'That's not the name yet, sweetie.' Whatever her name is, I know she'll run circles around him."
Hannah added that the couple hopes their kids' lives will be as "normal" as possible.
"They’re going to be born into such an extraordinary situation," she wrote. "They’re going to have to be some strong little people. We don’t want them to be defined by their dad’s name — for them, we want him to just be “Dad.” That will be the piece of him they’ll have that the rest of the world doesn’t. It will be special, and it will be theirs."
Photo Credit: Getty / Mike Coppola