Mark Zuckerberg pledged to give away 99% of his Facebook shares during his lifetime.

In celebration of becoming a father, the Facebook founder announced that he will donate about $45 billion of his fortune to a charity.

Zuckerberg made the announcement in a lengthy-letter to his newborn daughter, Max.

Mark and wife, Priscilla Chan, created the Chan Zuckerberg Initiative, with a mission to advance human potential and promote equality for all children in the next generation.

The couple wrote: “We will give 99% of our Facebook shares — currently about $45 billion — during our lives to advance this mission. We know this is a small contribution compared to all the resources and talents of those already working on these issues. But we want to do what we can, working alongside many others.”

Mark and Priscilla said the initial areas of focus of the initiative will be personalized learning, curing disease, connecting people and building strong communities.

“Any profits from investments in companies will be used to fund additional work to advance the mission,” they added.

Philanthropists such as Bill Gates and Bono congratulated the couple on giving away the majority of their wealth to charity.

Gates’ wife, Melinda, commented on the couple’s announcement: “As for your decision to give back so generously, and to deepen your commitment now, the first word that comes to mind is: Wow. The example you’re setting today is an inspiration to us and the world.”

Bono, meanwhile, said: “I can’t wait to see what they achieve, not just with their wealth, but by their example and with their ingenuity, creativity and vision applied to some of the biggest challenges — and opportunities — of our time.”

Zuckerberg and Chan have already donated more than $1.6 billion to charity in the past decade, Reuters noted. These include a $100 million gift to the Newark Public School System, a $25 million donation to the CDC to stop the spread of Ebola, and a $120 million commitment to education in the Bay Area.

In 2010, the Facebook CEO also signed the “Giving Pledge,” along with Gates, to give away the majority of his money, Business Insider wrote.