The MR BRIGHTSIDE singer recently fulfilled his lifelong dream and joined frontman Bono onstage during a Las Vegas, Nevada concert to sing his favourite U2 track IN A LITTLE WHILE with his idol, and he insists it was his proudest moment.
He says, "(Bono) is great, we've learned so much.
"I saw them on the Elevation tour when I'd never even played a gig, so it's such a strange thing that has happened to us.
"They're the best band in the world, no doubt about it, and they're the best live band at the moment, and it's an amazing thing.
"We've learned so much from watching all of them. We're just going to be good students."