Joining the two headliners on the outing--which kicks off Aug. 21 in Detroit--will be funk/soul act Robert Randolph [ tickets ] & The Family Band and Christian rock group Jars of Clay [ tickets ].

The trek will hit 23 cities from August through September, with a portion of funds raised during the tour going to local Habitat for Humanity affiliates in each city along the route. Performers on the tour will collectively donate one dollar to the organization for every ticket sold, according to a press release.

"We couldn't be more excited for this opportunity to play on the same bill with bands we respect, and to help an organization whose work we respect," Third Day bassist Tai Anderson said in a statement.

Third Day is set to release a new studio album, "Revelations," in July. The disc follows 2006's holiday-themed "Christmas Offerings," as well as a pair of best-of albums released last year: "Chronology Volume 1" and "Chronology Volume 2."

San Diego-based Switchfoot continues to tour the world behind its sixth album, 2006's "Oh! Gravity," which reached No. 18 on The Billboard 200. The record recently got a boost from MTV, which chose the title track as the theme song for reality show "Life of Ryan," according to a press release.

"Oh! Gravity" follows Switchfoot's two previous major-label releases: 2005's gold-certified "Nothing Is Sound" and the band's 2003 breakthrough album, "The Beautiful Letdown," which went double-platinum on the strength of hit singles "Dare You to Move" and "Meant to Live."