The songtress-turned-entrepreneur and her husband broke the news of Birdie’s arrival with a touching post on Instagram on Wednesday, featuring a black-and-white image of Maxwell holding her little sister’s hand.
“We are so happy and proud to announce the birth of our perfect daughter, Birdie Mae Johnson,” Simpson wrote alongside the image, adding that their new bundle of joy is 10 pounds, 13 ounces.
ET's source also shared that everyone at the hospital, including Jessica’s sister Ashlee Simpson and her husband, Evan Ross, Eric’s parents and Jessica’s parents, guessed the baby’s weight — and Jessica’s father, Joe Simpson, won!
"They're so excited, because they're only 14 months apart, so they didn't get to experience the excitement of each other," Simpson said. "But when I told them that we're having another baby, I know that they'll remember that for the rest of their lives."
The fashion designer went on to explain that her kids had begun asking all kinds of questions about her pregnancy and the birthing process, which has led to some wild family conversations.
"They are most excited about learning how to do the swaddle. Maxwell, my daughter, is just so happy that it's a girl," she said. "They ask me the craziest questions that I can't say on TV ... 'How does the baby come out?' 'Where does the milk come from, I don't understand!'"