Ben Harper [ tickets ] and the Innocent Criminals, who slowly built a large fan base through years of relentless touring, aren’t tinkering with that successful formula in 2001. The group is scheduled to open a month-long U.S. outing in mid-April, and tours of Japan and Europe will run through July.

Before Harper and his band embark on their tour’s U.S. leg--which opens on April 20 at the University of Pennsylvania--the group is scheduled to play three dates in Australia.

Harper’s schedule also includes a sold-out April 6 solo acoustic performance in the Southern California city of Claremont, as well as an April 7 taping of the ESPN Sports & Music Awards. (That show, at the Universal Amphitheatre near Los Angeles, will also feature appearances by Black Sabbath, De La Soul with Busta Rhymes, Incubus and Crazy Town.)

Virgin Records released Harper’s “Live from Mars,” a 25-song, two-CD set that was culled from two years of shows, on Tuesday (3/27). The first disc features Harper with his band, and the second his solo acoustic performances.

Jack Johnson will open for Harper from May 7 through May 27. Johnson’s debut album, “Brushfire Fairytales” (Enjoy), was released in February, and features Harper on slide guitar.