Welcome to the world, Sienna Princess Wilson. Ciara and Russell Wilson announced the birth of their first child together in an Instagram post Friday: "No matter how big the wave, we will always be your calm in the storm. We love you." The family is reportedly doing well after the birth of the baby girl, E! Online reports. The singer's pregnancy was announced back in October. While it's Ciara's first child with the Seattle Seahawks quarterback, she has a 2-year-old son from a previous relationship, according to TMZ. (More Ciara stories.)