“I was worried that there weren’t enough people who knew about us,” says Jeff Lynne, explaining his anxiety over reviving ELO to headline at an all-day festival in London’s Hyde Park in September 2014. 
We took a big chance. The crowd could’ve gone home any time, they didn’t have to wait around for us at the end. But it was still full. I remember looking through a little gap in the curtain and going: ‘They’re still here!’” 
https://www.loudersound.com/features/jeff-lynne-interview-from-elo-to-the-beatles-and-into-the-blue-sky