New York, Aug. 29 (AP): Facebook CEO Mark Zuckerberg and his wife are welcoming a new daughter in a post - where else - on Facebook.

Zuckerberg and Priscilla Chan already have a toddler daughter, Max, born in 2015. They named their second child August.

The couple posted a photo of the family today, along with a letter they wrote to August hoping she will get to enjoy her childhood. They write that "childhood is magical" and tell her that she only gets to be a child once "so don't spend it worrying too much about the future".

Chan and Zuckerberg also wrote a letter to Max when she was born, talking about the world they hope to see her grow up in, with advances in science, medicine and access to education.

Zuckerberg and Priscilla concluded the message to their newborn daughter with: "August, we love you so much and we're so excited to go on this adventure with you. We wish you a life of joy, love and the same hope you give us."