Complex sentence: The first artist was Justin Timberlake at London's Indigo at The O2 in 2016 and the second was Ed Sheeran at KOKO in Camden, London in 2017.
Split into simpler sentences: The first artist to do this was Justin Timberlake at London's Indigo at The O2 in 2016. The second artist to do this was Ed Sheeran at KOKO in Camden, London in 2017.