Plain old oatmeal is selling like hot cakes at Starbucks.

The coffee chain's newly introduced breakfast item has become its top-selling food, Reuters reports.

"It is the single highest volume [food] item in our history," said Michelle Gass, senior vice president of marketing at Starbucks, adding that "we believe we have hit a home run."

Starbucks added oatmeal to its menu earlier this month, Reuters said. The hot cereal comes with mixed nuts, dried fruit or brown sugar.

Click here to read the full Reuters report.