"Mick (Jagger) called me and said, 'You wanna sit in with us?' and I said, 'Let me think about it...?' It was fantastic... and before I knew it I was at soundcheck at the arena... They soundcheck for nearly two hours... all of them, and then took a break, and then did their two-and-a-half hour show. It's amazing; their stamina is insane." Keith Urban on performing with the Rolling Stones during their 50 & Counting tour opener in Los Angeles on Friday night (03May13).