Blakely, who has a net worth of $1 billion, founded the women's shapewear company at the age of 29.
In a letter to the Gates Foundation, Blakely vowed to focus her charitable efforts on women.
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!
I have so much gratitude for being a woman in America. I never lose sight that I was born in the right country at the right time. And I never lose sight of the fact that there are millions of women around the world who are not dealt with the same deck of cards upon their birth. Simply because of their gender they are not given the same chance I had to create my own success and follow my dreams. It is for those women that I make this pledge.
Other Giving Pledge participants include Michael Bloomberg, Richard and Joan Branson, Jon and Karen Huntsman, George Lucas, Elon Musk and Mark Zuckerberg.