Pat Metheny and Bruce Hornsby to join forces at Longwood Gardens

The pairing of Bruce Hornsby and Pat Metheny may initially seem odd - if you know the first solely as the hit-making singer-songwriter responsible for 1986's "The Way It Is" and the latter as an exceptionally fluid jazz guitarist.

But the Campfire Tour, which plays a sold-out show at Kennett Square's Longwood Gardens Thursday night, unites two friends and restless artists whose newest work continues to push against ready classifications and boundaries.

Metheny has been on the road nearly constantly since February, when Kin, the latest album by the Pat Metheny Unity Group, came out, and he invited Hornsby, who will be joined by drummer Sonny Emory, to open a set of 15 summer shows.

"To me, Bruce is in many ways one of the most misunderstood talents I know," Metheny says via e-mail. "People often don't realize first of all what an incredible pure musician he is. And there is no one remotely like him; he is instantly identifiable."

Hornsby first worked with Metheny two decades ago, when Metheny guested on Hornsby's Harbor Lights and Hot House albums.

Hornsby, for his part, calls Metheny's solos on those albums "transcendent."

"I would consider [the solos] to be the greatest contributions I've ever had on any of my records," Hornsby says, from a tour stop in Milwaukee.

Hornsby got his start playing Grateful Dead covers in his brother's band in Williamsburg, Va., in the mid-'70s. In addition to his early pop hits such as "Mandolin Rain" and "The Valley Road" with his band The Range, he has explored blues and bluegrass, jazz and electronica. On Solo Concerts, a double-album due later this month culled from live performances in 2012 and 2013, he adds modern classical music to the mix.

"I've been interested for years in traditional American styles, like blues, boogie, New Orleans piano, folk, the hymnal," says Hornsby. "That's always been in my music, but more so even now, in the last few years. But I've also been really interested in modern classical music, with that dissonant, chromatic harmonic language that is used. So, this record, a whole lot of it anyway, is about the juxtaposition and combination of those elements."

To that end, alongside a wide selection of his own tunes, old and new, he plays compositions by Olivier Messiaen, Arnold Schoenberg, and Anton Webern, 20th-century European composers who explored atonality and dissonance. He integrates into his own song "Preacher In The Ring" a bit of "Caténaires" by American modernist Elliott Carter, and explores a similar style in the humorous new song "Life In The Psychotropics."

The modern compositions are challenging, but he has found they're not challenging for audiences. He knows that terms like atonality, twelve-tone, and dissonance can be "difficult" for a mass audience. But he relishes adding these to his concert vocabulary. "It's all about finding the proper context for these intrusions," he says with a laugh.

Hornsby and Metheny share a foundational love for traditional American music in its many variations. "Between the two of us," says Metheny, "we cut a pretty wide swath through a bunch of subsets of 'American' music that are pretty idiosyncratic to the way that we both have a sound that somehow couldn't come from anywhere else."

As he says of Hornsby, Metheny is "instantly identifiable." Since his first album as a leader, 1976's Bright Size Life, the Missouri native has pushed his liquid-toned guitar playing in ever-widening circles, from his classic work with keyboardist Lyle Mays in the Pat Metheny Group, through his collaborations with Ornette Coleman, Joni Mitchell, Charlie Haden, and Brad Mehldau, to his recent experiments with the Orchestrion, an elaborate hybrid instrument, to his 2012 Grammy-winning quartet Unity Band.

For Kin, Metheny expanded the Unity Band - saxophonist Chris Potter, bassist Ben Williams, and drummer Antonio Sanchez - to include multi-instrumentalist and vocalist Giulio Carmassi. They stretch out on hard-edged long-form songs such as "On Day One," which also incorporates the Orchestrion, and they ease into the gospel-flavored melody of "Born."

"This is an incredible band - maybe the best band I have ever had," Metheny says. "I added one more musician, and the record that we just made, Kin, is a very different kind of thing. If the first one was a black-and-white documentary, this is the 3D IMAX version of what that band can be. With this group, I can really cover everything from throughout my whole career all under one roof."

The Unity Group shows have included compositions from throughout that long career as well as some collaborative moments between Metheny and Hornsby.

"To me, the final and most important aspect of being a musician is what happens live on stage," Metheny says. "Everything leads to what we are doing now, which is going out and playing."

Concert

Pat Metheny, Bruce Hornsby

7:30 p.m. Thursday, Longwood Gardens, 101 Longwood Rd., Kennet Square

Sold out. Information: 610-388-1000, www.longwoodgardens.org