Music stars such as Britney Spears, Michael Buble, Robbie Williams and Alicia Keys will take to a London stage over the coming days to perform at the Apple Music Festival, with veteran Elton John kicking off proceedings on Sunday. The Grammy Award winning singer-songwriter sat behind the piano to belt out his famous hits such as Tiny Dancer and Don’t Let the Sun Go Down on Me with other performers including Christine and the Queens and Parker Millsap. The Apple Music Festival runs until September 30.