Oprah Winfrey has purchased a 10 percent share of Weight Watchers International Inc. and is a new member of the company's board of directors, Weight Watchers announced Monday.

She also has joined the program and will share her experiences and perspective along her weight loss journey, according to a release from Weight Watchers. Winfrey will use the Weight Watchers mobile app and work with a personal coach. 

In her new role, Winfrey will bring insight and strategy to program development and execution that reflects not only her own experiences as a member but also her unique ability to inspire and connect people to live their best lives, the release said.

"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 the release. "I believe in the program so much I decided to invest in the company and partner in its evolution."

Winfrey purchased newly issued shares representing 10 percent of the shares outstanding and will receive options to acquire an additional 5 percent of the fully diluted shares. Reports are that the 10 percent stake cost Winfrey about $43.2 million.

Wall Street reacted to the announcement with the stock of the publicly traded company (NYSE: WTS) jumping from a close of $6.79 on Friday to a mid-day price of $14.08 per share. For the past 52 weeks, the company has traded at $3.67 per share on the low end to $29.84 on the high end.

"We are expanding our purpose from focusing on weight loss alone to more broadly helping people lead a healthier, happier life," said Jim Chambers, president and CEO of Weight Watchers. "Through our conversations, it became clear that there is tremendous alignment between Oprah’s intention and our mission. We believe that her remarkable ability to connect and inspire people to realize their full potential is uniquely complementary to our powerful community, extraordinary coaches and proven approach."

Ray Debbane, chairman of the company's board of directors, said: "Weight Watchers and Oprah Winfrey make a powerful combination. Oprah is a force of nature in connecting with people on a very personal level to live inspired lives. This partnership will accelerate our transformation and will meaningfully expand our ability to impact many millions of people worldwide."

In late September, Weight Watchers announced the formation of its latest Scientific Advisory Board under Gary Foster, Ph.D., chief scientific officer. This panel of 10 individuals was enlisted to inform and advise the company as Weight Watchers continues to develop offerings based on the latest scientific evidence.