"I'm not letting go, I'm not letting go..." #FierceDuo This image appears in the gallery:One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015 125. "I'm not letting go, I'm not letting go..." #FierceDuo Picture: Danny North 171 images See the full gallery: One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015