March 6 (Reuters) - Media mogul Oprah Winfrey sold a portion of her holdings in Weight Watchers International Inc, the former talk show host's production company Harpo Inc said on Tuesday.

A portion of the shares were donated to Winfrey's foundation and she will retain over 75 percent of her holdings in the weight management company, Harpo said in a statement.

Winfrey will not sell additional shares this year, it added.

"I am deeply committed to Weight Watchers and continue to see a bright future for the company," said Winfrey, who is continuing in her role as board member, adviser and spokesperson.

In 2015, Winfrey joined Weight Watchers' board and took a 10-percent stake in the company, with options to buy more.

Weight Watchers' stock have gained more than eight times in value since she bought into the company. (Reporting by Subrat Patnaik in Bengaluru; editing by Diane Craft)