Keith Urban stepped in for Rascal Flatts during a Kenny Chesney concert Sunday night (July 11) in Hartford, Conn., because Rascal Flatts' lead singer Gary LeVox is on voice rest. Urban performed without a band. "It was the coolest thing," Chesney said. "Keith just walked out onstage, plugged in and did a show that was just him and the guitar. It's a whole other way to see him -- and he rocked." Rascal Flatts are expected to perform at Chesney's next tour date -- Thursday night (July 15) in Birmingham, Ala.