Spanx Founder Sara Blakely Makes 'The Giving Pledge'

Spanx founder (and self-made billionaire) Sara Blakely, a Buckhead resident, has reached another milestone: she's now part of The Giving Pledge, Forbes reports.

The Giving Pledge is "a commitment by the world's wealthiest individuals and families to dedicate the majority of their wealth to philanthropy," its website states. The pledge is an effort of Bill and Melinda Gates and Warren Buffet.

Blakely's pledge letter, posted on The Giving Pledge's website and also attached to this article, promises to invest in women. The letter begins:

Since I was a little girl I have always known I would help women. In my wildest dreams I never thought I would have started with their butts. As it turns out,  that was a great place to start! At Spanx we say it's our goal to make the world a better place, one butt at a time. With my pledge my goal is to make a world a better place...one woman at a time.

Blakely, who made Forbes' billionaire list and graced its cover in 2012, joins Atlanta Falcons owner and billionaire Arthur Blank on The Giving Pledge list.