On Oct 19, the 61-year-old media mogul invested in Weight Watchers by purchasing a 10 percent stake in the company, a move that almost doubled the price of a single Weight Watchers share. The result? A $70-million profit for Oprah Winfrey made in just one day.

“I believe in the @weightwatchers program so much I decided to invest, join the Board, and partner in #wwfamily evolution,” the Oscar-nominated actress said.

After Winfrey purchased 6.4 million shares of Weight Watchers investors immediately followed suit, increasing the initial value of the share from $7 to almost $14.

What’s more, $70-million earnings in a single day are pocket change for Winfrey whose estimated fortune is $3 billion.

Winfrey joined the board of Weight Watchers and will act as an advisor as well as a member of the program who will share her experience with other users of company products.

“Weight Watchers has given me the tools to begin to make the lasting shift that I and so many of us who are struggling with weight have longed for,” Winfrey said in a statement. “I believe in the program so much I decided to invest in the company and partner in its evolution.”