Calvin Harris won't work with Taylor Swift

British DJ Calvin Harris has reportedly turned down an offer to work with his girlfriend Taylor Swift, fearing that it would put a strain on their relationship. “Calvin’s next single is ready but the label is keen for him to get a big female US star to collaborate on it. They floated the idea of him working with Taylor but he politely declined it. Calvin has seen how sour things can turn when working with someone he’s dating,” a source told The Sun. Calvin has earlier collaborated with Rita Ora, whom he had dated for a while.