Calum Hood of 5 Seconds Of Summer shows off his music skills for the Summertime Ball crowd. This image appears in the gallery:5SOS Live At The Summertime Ball 2014 6. Calum Hood of 5 Seconds Of Summer shows off his music skills for the Summertime Ball crowd. Picture: PA 9 images See the full gallery: 5SOS Live At The Summertime Ball 2014