John Diamond (1823 – October 20, 1857), aka Jack or Johnny, was an Irish-American dancer and blackface minstrel performer. Diamond entered show business at age 17 and soon came to the attention of circus promoter P. T. Barnum. In less than a year, Diamond and Barnum had a falling-out, and Diamond left to perform with other blackface performers. Diamond's dance style merged elements of English, Irish, and African dance. For the most part, he performed in blackface and sang popular minstrel tunes or accompanied a singer or instrumentalist. Diamond's movements emphasized lower-body movements and rapid footwork with little movement above the waist.