McGraw and Hill's 2006 "Soul2Soul II Tour" was the highest-grossing country outing in history, as well as the 12th highest-grossing tour of all time, according to concert industry magazine Pollstar. The 73-concert, 55-city trek was also the fastest-selling tour for the first quarter of 2006, according to Ticketmaster (LiveDaily's parent company).

"Soul2Soul 2007" is expected to include some of the 35 No. 1 singles the couples have amassed between them, as well as new music, a new production and a new sponsor. Details about the tour will be announced as they become available at McGraw's website and Hill's website.

Meanwhile, on March 27, McGraw is set to release "Let It Go," his first studio album in nearly three years. "Reflected: Greatest Hits V. 2," which surfaced last March, became McGraw's ninth consecutive record to debut at No. 1 on the Billboard Country Album chart, according to a press release.

Hill's last three albums, including 2005's multi-platinum "Fireflies," each debuted consecutively at No. 1 on The Billboard 200 album chart, as well as the magazine's Top Country Albums chart. She is the only female artist to accomplish that feat, according to a statement on her website.

Both Grammy-winning entertainers have been nominated in the first round of the 2007 CMT Music Awards, which are determined by fan voting.