John Mayer and Taylor Swift may record a duet after Mayer posted a message on Twitter in March that he was going to finish a new song, "Half of My Heart," and that he wanted it to sing with Swift. In an interview with Elle magazine, Swift said she "freaked out" when she heard about the message because she's been one of his longtime fans. Last month, Mayer and Swift performed his "Your Body Is a Wonderland" and her "White Horse" together during her concert in Los Angeles.