PITTSBURGH, May 5, 2015 /PRNewswire/ -- GNC Holdings (GNC) has announced a new partnership with the Bonnaroo Music & Arts Festival, which takes place this year from June 11-14 in Manchester, Tennessee. As part of the partnership, GNC will execute a multi-faceted strategy that consists of on-site experiences, outbound media and GNC support, before, during and after the festival.