Mark Zuckerberg second baby
Mark Zuckerberg and his wife Priscilla Chan welcomed their beautiful baby girl to the world with a touching Facebook postFacebook/Mark Zuckerberg

Facebook CEO Mark Zuckerberg and his wife Dr Priscilla Chan welcomed their second daughter with a touching open letter on childhood. The proud couple aptly named their baby girl August and posted a sweet photo of their family in a Facebook post on Monday (28 August).

Like they did with their first daughter, Maxima, the couple penned an open letter to August saying: "You only get to be a child once, so don't spend it worrying too much about the future."

Shortly after Max was born in November 2015, they announced the creation of the Chan Zuckerberg Initiative in an open letter to their newborn and pledged to donate 99% of their Facebook shares during their lifetimes to "advance human potential and promote equality".

"When your sister was born, we wrote a letter about the world we hoped she and now you will grow up in - a world with better education, fewer diseases, stronger communities, and greater equality," Zuckerberg wrote in the post. "But rather than write about growing up, we want to talk about childhood. The world can be a serious place. That's why it's important to make time to go outside and play.

"Childhood is magical. You only get to be a child once, so don't spend it worrying too much about the future. You've got us for that, and we'll do everything we possibly can to make sure the world is a better place for you and all children in your generation."

They encouraged August to keep reading her favourite Dr Seuss books, hoped she would ride the carousel with Max "until you've tamed every colour horse", run as many laps around the living room and yard and take plenty of naps.

"I hope even in your dreams you can feel how much we love you," they continued. "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."

Zuckerberg's post immediately drew warm messages of congratulations from social media users around the world.

"Such a sweet photo. Congratulations to Mark, Priscilla, Max and to August for choosing a wonderful family," Facebook's head of recruitment Miranda Kalinowski wrote.

Lars Rasmussen, the co-founder of Google Maps and Facebook's former engineering director, wrote: "Congratulations to the 4 of you!!! The three of us are beyond happy for you. Also: girls are the best."

"Thank you Mark and Pricilla for sharing this wonderful moment with the FB family! Sooo special! Beautiful name, beautiful family. I'm sure Max will love being a big sister," one Facebook user wrote.

The tech executive said earlier this month that he will take two months of paternity leave after the birth of his second daughter. He will take time off during the baby's first month and later spend the entire month of December with his family.

"I'm looking forward to bonding with our new little one and taking Max on adventures", Zuckerberg said.

The tech executive said earlier this month that he will take two months of paternity leave after the birth of his second daughter. He will take time off during the baby's first month and later spend the entire month of December with his family.

"I'm looking forward to bonding with our new little one and taking Max on adventures", Zuckerberg said.