Oprah Winfrey
The value of Oprah Winfrey’s 10% stake in Weight Watchers International has shot up from $43.2m to $148mGetty Images

The shares of Weight Watchers International, a weight loss company in New York, soared after a TV commercial starring Oprah Winfrey was aired. The shares have risen since October after Winfrey bought a 10% stake in the company.

The shares jumped up about 18%, says the beanstockd. In the commercial, several videos of Winfrey working out are shown. They also talk about her struggle with weight. The advertisement concludes with Winfrey asking viewers to join her. "Let's do this together," she says. Winfrey tweeted the commercial to her fans.

She was brought into Weight Watchers International to save it. The company's popularity kept dipping even as fitness crackers and other free food-tracking apps caught on.

Despite the surge, the shares of the company that deals in dieting products still remain down by a third over last year. Beanstockd added: "The rapid movement of Weight Watchers International could be explained by the company's new outlook on weight loss, which they call the "Beyond the Scale" programme.

"Winfrey knows all about reinventing yourself and successfully losing weight, but she also knows how to pay attention to trends. As such, her partnership with Weight Watchers International seems to have encouraged a new type of weight loss programme, one that takes a personalised approach to healthier eating, fitness, and personal development."

The Detroit Free Press said the media baroness has grown many times richer. In October, Winfrey paid about $43.2m (£29.13m) for her 10% stake in Weight Watchers. That stake is now worth more than $148m (£998.60m).