It is difficult to believe that it was just five years ago that Sugarland was opening for country superstar Kenny Chesney and he was shifting media interviews to them.

Now, of course, the duo of Kristian Bush and Jennifer Nettles are major country stars in their own right. And although the newly married Nettles just announced she's pregnant, it doesn't seem that will slow the duo down this summer. In a way, the birth of Nettles' first child reflects the birth of the duo's music diversity.

"It wouldn't surprise me to find a Metallica fan or a Gwen Stefani fan that is also a Sugarland fan," said Bush in a past interview with The Washington Examiner. "If you look at the iPod of a Sugarland fan, it probably looks like mine -- a lot of different types of music."

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Indeed, Sugarland has shaken some country loyalists by building its career big mixing and matching musical formats. A bit of country here. Some rock there. Some Amy Winehouse soul there.

That likely comes as a way to heal from the tragic stage collapse during their show at last year's Indiana State Fair. Seven people died in the incident.

Although fallout from that fatal accident continues, the duo is trying to make this year's tour as fan-friendly as possible. This year's "In Your Hands" tour puts the show in the control of fans, who vote for the playlists in each city.

In addition, fans who upload videos of themselves singing the Grammy Award-winning duo's song "Baby Girl" will be eligible for prizes, including a chance to sing on stage with the duo.

In a way, the duo is paying back Chesney and others who gave them a chance at stardom early in their career when "Baby Girl" was their first hit. Since then, of course their hits have included songs "Just Might (Make Me Believe)," "Already Gone, "All I Want To Do," "Stuck Like Glue" and more.

The two credit their success with their willingness to break the Nashville, Tenn., mold that often keeps performers and songwriters in separate camps. Nettles and Bush said Nashville has welcomed them as both writers and entertainers.

"We had a lot of fun just writing this record from start to finish," said Nettles of "The Incredible Machine." "I think when the songs are there, the music is there, you will hear it in the recordings."