David Guetta, Afrojack, and Sia appeared onstage together at Miami's Ultra Music Festival to perform their hit "Titanium" live for the first time.

The surprise performance of the 2011 classic happened on the festival's main stage during a headlining set by Afrojack.

These guitarists – 18-year-old Yasemin aka Jellybean, 16-year-old Zakia, 14-year-old Shukriya, and seven-year-old Uzra – are ...