MacKenzie Bezos Just Pledged to Give Away Half Her $37 Billion Fortune During Her LifetimeShe became one of the richest women in the world in April after finalizing the terms of her divorce from Amazon CEO Jeff Bezos.

MacKenzie Bezosannounced on Tuesdaythat she had joined the philanthropic effort known as theGiving Pledge, in which participants promise to give away more than half of their wealth during their lifetime or in their will.

Followingher divorce fromAmazon's founder, Jeff Bezos, earlier this year, MacKenzie Bezos received a stake in the retail giant that puts her net worth at almost $37 billion, according to current prices.

"We each come by the gifts we have to offer by an infinite series of influences and lucky breaks we can never fully understand," Bezoswrote in her letter. "My approach to philanthropy will continue to be thoughtful. It will take time and effort and care. But I won't wait. And I will keep at it until the safe is empty."

The Giving Pledge,started almost a decade agoby Warren Buffett and Bill Gates, is signed by some of the wealthiest families and people in the world. Other tech billionaires who havejoined the pledge includeMark Zuckerberg and Priscilla Chan, the Airbnb cofounder Brian Chesky, and the LinkedIn cofounder Reid Hoffman.

Notably, the world's richest person has refused to sign on to the Giving Pledge: Jeff Bezos, whohas a net worth of $131 billion, is theonly American ranked in the top five on the Bloomberg Billionaires Indexof the world's richest to not join on to the charitable pledge. His latest effort to give away to charity was a $2 billion donation in September, whichreportedly represented about 1.3% of his net worthat the time.

Still, Jeff Bezospraised his his ex-wife on Tuesdayfor her Giving Pledge commitment.

"MacKenzie is going to be amazing and thoughtful and effective at philanthropy, and I'm proud of her," Bezos said on Twitter. "Her letter is so beautiful. Go get 'em MacKenzie."

The Bezoses announced in early Aprilthat they had finalized the terms of their divorce. Under the agreement, MacKenzie Bezos granted the Amazon CEO all her interests in The Washington Post and Blue Origin, as well as 75% of the Amazon stock they owned and voting control over the shares she retained.

The terms of the divorce left MacKenzie Bezos with a stake in Amazon worth almost $37 billion, placing her in the top five amongthe world's richest women.

MacKenzie Bezoswas one of the first employeesat Amazon, and she has written two award-winning novels. MacKenzie and Jeff Bezos had four kids over their 25-year marriage.