From Wikipedia:
In 1968, NBC-TV invited Clark to host her own special in the U.S., and in doing so she inadvertently made television history. While singing a duet of "On the Path of Glory," an anti-war song that she had composed, with guest Harry Belafonte, she touched his arm, to the dismay of a representative from the Chrysler Corp., the show's sponsor, who feared that the brief moment would offend Southern viewers at a time when racial conflict was still a major issue in the U.S. When he insisted that they substitute a different take, with Clark and Belafonte standing well away from one another, Clark and her husband Wolff, the producer of the show, refused, destroyed all other takes of the song, and delivered the finished program to NBC with the touch intact. The program aired on April 8, 1968, with high ratings and critical acclaim (To commemorate the 40th anniversary of the original telecast, Clark and her husband, who had served as executive producer of the show, appeared at the Paley Center for Media in Manhattan on September 22, 2008, to discuss the broadcast and its impact, following a broadcast of the program.)