Singer Taylor Swift to star in Diet Coke advertising campaign ATLANTA, Jan. 29 (UPI) -- Diet Coke says U.S. country music star Taylor Swift has signed on to star in its new advertising campaign. Taylor's unmatched business savvy, talent and drive to succeed are an inspiration to everyone. She's an extraordinary individual and a wonderful symbol of achievement," Katie Bayne, president of North America brands for The Coca-Cola Co., said in a statement Monday. Taylor tells us that every day Diet Coke plays a small part in helping her stay extraordinary. It's one of the many reasons she's the ideal partner to represent our brand. I've said for years that Diet Coke just 'gets me' and my lifestyle. I'm so excited about our new partnership," said Swift.