 Swift desired for Caillat to sing background vocals but in a loud manner , enough for audiences to recognize who sang backup . Originally Swift and Caillat were only to harmonize in the chorus , but as Caillat recorded , Swift decided to include her voice more throughout the track because of how impressed she was . Swift first recorded the entire song , and Caillat then recorded background vocals separately . Swift was very pleased with the finished product : " I think she sounds beautiful on it . I 'm so excited to have her voice on my album . " 
