80,000 people were singing along to a medley of Olly's most famous songs This image appears in the gallery:One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015 147. 80,000 people were singing along to a medley of Olly's most famous songs Picture: Danny North 171 images See the full gallery: One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015