Weight Watchers International (NYSE: WTW) caught lightning in a bottle with its Oprah Winfrey partnership. Since the media mogul took a 10% stake in the company in 2015, shares have exploded on the back of increased membership growth as Oprah has helped reposition Weight Watchers from a weight-loss program to more of a lifestyle brand.Understandably, Weight Watchers is looking to recreate lightning in a bottle while expanding its demographic reach.