Mark Zuckerberg, the 26-year-old founder and CEO of Facebook, has joined dozens of other billionaires in pledging to give away the majority of his wealth to charity.

Zuckerberg, whose net worth is estimated to be at least $4 billion, announced Thursday that he would join the Giving Pledge, a philanthropic effort organized by Warren Buffett and Bill Gates to encourage the wealthiest Americans to give away their fortunes.

“People wait until late in their career to give back. But why wait when there is so much to be done?” Zuckerberg said in a press release. “With a generation of younger folks who have thrived on the success of their companies, there is a big opportunity for many of us to give back earlier in our lifetime and see the impact of our philanthropic efforts.”

In total, 57 families across the country have signed up to give away the majority of their wealth, including icons like Ted Turner, Michael Bloomberg and George Lucas, all of who have signed the pledge.

But the fact that Zuckerberg chose to commit the bulk of his wealth to charity is particularly notable because of his age. He is by far the youngest member listed on the Giving Pledge. Neither he nor anyone else on the list has declared the exact amount that they will give, but the goal is to give the majority of their wealth to charities of their choice over time.

“Mark’s decision to give big and give early is critically important. I think it’s a signal to other young people who are earning and controlling more money at a younger age than ever before that we can give now to change our world, we don’t have to wait,” said Jason Franklin, a professor of philanthropy at New York University and head of Bolder Giving, a nonprofit organization based in New York City.

“I think that Mark’s giving is just another sign of an increasing expectation among those in Generation Y that part of their success will be that they give back actively,” Franklin added.