In addition to the birth announcement – made through Facebook, of course – Mark Zuckerberg penned a sweet letter to his newborn daughter August

Mark Zuckerberg just updated his Facebook status – to read father of two!

The tech mogul announced the arrival of his second daughter with wife, Dr. Priscilla Chan, on – where else? – the social media site, Monday. August joins big sister Maxima “Max”, 20 months.

Alongside a sweet new family photo, Zuckerberg shared a letter to his newborn – a tradition created when Max first arrived.

In the note, Zuckerberg welcomed August to the world, adding, “Your mom and I are so excited to see who you will become.”

The 33-year-old said he wanted to “talk about childhood,” writing, “The world can be a serious place. That’s why it’s important to make time to go outside and play.”

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Credit: Mark Zuckerberg/Facebook

“You will be busy when you’re older, so I hope you take time to smell all the flowers and put all the leaves you want in your bucket now,” he told August. “I hope you read your favorite Dr. Seuss books so many times you start inventing your own stories about the Vipper of Vipp. I hope you ride the carousel with Max until you’ve tamed every color horse.”

Sharing a long list of hopes and dreams for his second-born, Zuckerberg also added some levity, writing, “I hope you’re a great sleeper.”

“And I hope even in your dreams you can feel how much we love you,” he added, continuing, “Childhood is magical. You only get to be a child once, so don’t spend it worrying too much about the future.”

Said the proud papa – who signed the letter from “mom and dad” – “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 and Chan announced their second pregnancy in March, revealing at the time the difficulties they’d had trying to conceive Max, which included three miscarriages.

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“We weren’t sure what to expect or whether we’d be able to have another child,” Zuckerberg wrote on Facebook. “When Priscilla and I first found out she was pregnant again, our first hope was that the child would be healthy.”

The post continued, “My next hope was that it would be a girl.”