MacKenzie Bezos has announced that she will give half of her fortune to charity in the aftermath of her divorce from Amazon founder Jeff Bezos.

Ms. Bezos released a letter on Tuesday announcing she’s signing on with the Giving Pledge, an initiative set up by Bill Gates and Warren Buffett to encourage fellow billionaires to promise half of the money they make in their lifetimes to philanthropic causes. While she didn’t say what kind of charity she plans on donating to, Bezos wrote of “the desire to be of service” in her letter and a desire to see her wealth go to constructive causes.

Bezos’ is estimated by CNN to have a net worth of approximately $37 billion, having become one of the richest people in the world after her divorce settlement with her ex-husband. Ms. Bezos joined the pledge with a group of 18 other new signers, including cryptocurrency executive Brian Armstrong, WhatsApp co-founder Brian Acton and financier David Harding.

From the letter:

“We each come by the gifts we have to offer by an infinite series of influences and lucky breaks we can never fully understand. In addition to whatever assets life has nurtured in me, I have a disproportionate amount of money to share. 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.”

[Photo via Jorg Carstensen/AFP/Getty Images]