Anderson Cooper's family is growing. The CNN anchor on Thursday night surprised viewers by announcing the birth of his second baby, Sebastian Luke Maisani-Cooper. Cooper's ex, Benjamin Maisani, who remains his "best friend," is raising Sebastian and his older brother, Wyatt, alongside Cooper, and is currently in the process of adopting Wyatt so he will be the legal father of both boys alongside Cooper. "Wyatt calls me 'Daddy' and Benjamin 'Papa.' We're a family," Cooper said, noting that Wyatt's last name will soon be changed from Cooper to Maisani-Cooper. Watch Cooper's announcement and see baby pictures here, or, for more on why Cooper and Maisani are raising children together, see here. (More Anderson Cooper stories.)