“MacKenzie is going to be amazing and thoughtful and effective at philanthropy, and I’m proud of her," Bezos tweeted. "Her letter is so beautiful. Go get ‘em MacKenzie.”
The Amazon founder and CEO also included her letter where she made her announcement.
The novelist announced that she signed The Giving Pledge, a campaign created by billionaire Warren Buffett, Microsoft co-founder Bill Gates and his wife Melinda Gates, to prompt the ultra-wealthy to pledge at least half their fortune to charitable causes.
MacKenzie did not say how she planned on giving her money away. She was one of the 19 new individuals and couples to sign the commitment Tuesday morning. The total number of givers in the philanthropy group has climbed to 204 since the billionaires started it back in 2010.
The divorce from the Amazon CEO would leave her with a 4 percent stake currently worth more than $36 billion in the online shopping giant.
The two announced they were getting divorced after 25 years of marriage in January. They have four children together. In April, the duo announced they had “finished the process of dissolving” their marriage.
Fox Business’ Jennifer Earl and The Associated Press contributed to this report.