For one thing, the company was named the fourth-best diet in US News & World Report's new ranking of eating plans on Wednesday.
Additionally, major investor and board member Oprah Winfrey tweeted a new advertisement supporting the company. The ad features Winfrey claiming to have lost over 40 pounds since starting on Weight Watchers and encourages others to "take the leap" by signing up for the plan.
Following both pieces of news, the stock is up over 20% on the day as of 1:15 p.m. ET.
This isn't the first time an ad from Winfrey has moved the needle for the weight loss company. In January 2016, Winfrey tweeted out an ad touting a 26 pound weight loss and Weight Watchers stock subsequently leaped by 20%.
