R&B singer Green, who is also playing both events, invited the cult stars to join him on his own plane - but they turned down the offer so they could have more time in California.

Arcade Fire drummer Jeremy Gara explains, "It was an option to go with Cee Lo but we're not doing it because he plays then leaves straight away.

"We're arriving (in London) on Tuesday and get off the plane and go straight to the O2 Arena to rehearse."