How important is song choice on American Idol? A lot, according to Keith Urban.

I had the chance to catch up with Urban and talk about the remaining contestants and how much song choice matters as the 13th season inches its way closer to a winner.

"Song choice matters -- a lot. For some more than others," Urban told me during a phone interview Wednesday (April 2). "I mean, I think there's some artists in this group who can sing most things, and I think their vocal and their artistry comes through no matter what they're singing. But I think other ones really have to pick their songs carefully to play to their strengths."

Dexter Roberts, who I've had my eye on since he became the last remaining country singer in the group, has done well picking tunes -- contemporary ones and some older ones. But not the same old, same old country hits from the same short list of A-list artists, either.

And Urban admitted making those decisions can be hard on the contestants when they're getting some mixed messages.

"It's tricky," he said. "I know it can seem contradictory that we ask everybody to show us something different. But you also have to know how to be different and still remain yourself. It's showing another side of you. Not just this complete other thing that's got nothing to do with who you are."

This week's theme is "Back to the Start," and the Top 8 hopefuls will be singing the songs they auditioned with. So for Roberts, that will be Casey James' "Drive."