Gill knew it would be tough to cover Sting's material, and he told the rock singer he'd need him to step in during some moments.
"I'm meat and potatoes, you know, but once I ... went in there and spent the time, I started to understand how it all worked," he said. "There's like a couple lines that I've tried to learn and I just said, 'Sting, you gotta sing these 'cause they're so off-the-hook great I don't want to screw them up.'"
They also said their temporary duo was drama-free.
"We haven't had a fight yet. Not one," said Sting.
Gill chimed in with a laugh: "If we get into a fight, I'll choke you with heel dust (and) run away. I'm not much of a fighter."
Mesfin Fekadu covers entertainment for The Associated Press. Follow him on Twitter at http://twitter.com/musicmesfin