MacKenzie Bezos, who in April finalized her divorce from Amazon founder and CEO Jeff Bezos -- the world's richest man -- is vowing to donate at least half of her wealth to charity. 

 

Bezos, who is worth an estimated $37 billion, announced in a letter published Tuesday that she will sign the "Giving Pledge," a philanthropic campaign founded by celebrated investor Warren Buffett.

"My approach to philanthropy will continue to be thoughtful," Bezos wrote. "It will take time and effort and care. But I won't wait. And I will keep at it until the safe is empty," also noting that she has "a disproportionate amount of money to share." 

The Giving Pledge, founded in 2010 by Buffet and Bill and Melinda Gates, has drawn 204 pledgers. Absent from the pledge's list of supporters is Jeff Bezos, who is worth an estimated $150 billion. 

MacKenzie Bezos is the founder of Bystander Revolution, an organization committed to anti-bullying efforts.