"We wanted to continue to grow and expand the experience for the fans," the couple said in a press release. "We have a personal connection with all of these artists and their music and look forward to them joining us on tour."

A second stage outside arenas on the tour will feature talent handpicked by McGraw himself, according to the tour's publicist. The "MyGIG Infotainment Stage" will feature Halfway to Hazard and Lance Miller, whose Warren Brothers-produced debut single, "She Really Loves Me," was recently released on WB Records.

The trek, which now comprises 44 dates, is scheduled to make stops at arenas across the US and Canada through mid-August. The nine-show Canadian leg marks McGraw and Hill's first string of co-headlining stops throughout that country.

The two-and-a-half-hour Soul2Soul production again will be configured in the round and include several first-time performances by the couple as well as many solo hits by each singer.

Last year's Soul2Soul outing was the highest-grossing country music tour in history and the 12th highest-grossing tour of all time, according to concert-industry publication Pollstar.

Between the two of them, McGraw and Hill have sold more than 64 million albums. Last month, McGraw released his 11th set, "Let it Go," which is his ninth consecutive record to debut at No. 1 on Billboard's Top Country Albums chart. Hill's last three albums, including 2005's "Fireflies," each debuted at No. 1 on The Billboard 200 album chart as well as the magazine's Top Country Albums chart--a first for a female artist.

McGraw and Hill recently announced that they will play their only outdoor gig this year at the Sept. 1 Country Rocks the Hill event in Moncton, New Brunswick.