At first glance, it may seem a pairing as discordant as oil and water: Pop chart-topper and former Grateful Dead pianist Bruce Hornsby with bluegrass sensation Ricky Skaggs. But the two musicians have more in common than their respective Grammy awards.

Friends since the 1980s, the two artists have collaborated on several projects, including "Ricky Skaggs and Bruce Hornsby," the duet album released last year on the Sony/Legacy label. The album, an energized collection of Hornsby originals and traditional Appalachian folk tunes backed by Skaggs' terrific band, Kentucky Thunder, set the stage for the tour that brings Skaggs and his band and Hornsby to Progress Energy Center's Meymandi Concert Hall on Wednesday.

The musicians met while performing at a concert. Skaggs was a top-selling country artist, while Hornsby was riding high with "Mandolin Rain," "The Way it Is," and other hits. Hornsby invited Skaggs and his band on stage to jam, and the musicians discovered a mutual fondness for their respective talents.

When Skaggs was choosing artists for "Big Mon," a CD tribute to bluegrass founder Bill Monroe in 2000, he made Hornsby's version of the Monroe Brothers' classic, "Darling Corey," the lead track for the CD. The collaboration led to an interest in doing more projects together.

"It seemed like every time we got together to play, sparks flew," says Skaggs, whose trophy room includes 13 Grammy awards along with numerous honors from the bluegrass community. "We felt there was something deeper than just a song or two. For the 'Big Mon' project, he was the first guy to sign up and first to come record. That became the benchmark for the rest of the record. I felt it would have to be that good. I'm glad we started with that song, because it had such a sound of newness, freshness -- yet it was something old. So we said then that we had a destiny of making more music together."

When Hornsby, a three-time Grammy winner, signed with Sony Records, he told them that he wanted to record a bluegrass album with Skaggs. The label agreed, and the project got under way in 2006.

"We got together and cut a few tracks," Skaggs recalls. "We sent some songs back and forth to each other, and we just loved what we were getting. What he wanted was just to play with me and Kentucky Thunder. He loved this band and its sound, and he loved the musical abilities and felt he could hang with us."

Skaggs says that when assembling the play list for the album, the musicians wanted to ensure that the selections would appeal to fans of each artist. Skaggs' fans enjoy such old-time fare as Kentucky banjoist Roscoe Holcombe's "Across the Rocky Mountains," while Hornsby serves up the whimsy of "The Dreaded Spoon" and reprises "Mandolin Rain."

Skaggs and Hornsby take the same approach to their live performances, often working up songs that are not on the album. The goal is to keep the performances fresh for the musicians, and familiar to their fans.

They might, for example, blaze through such Kentucky Thunder favorites as "Sally Jo," "Little Maggie," or "How Mountain Girls Can Love," while adding such Hornsby staples as "White Wheeled Limousine," "The End of the Innocence," or "The Valley Road." They may also showcase songs from "Honoring the Fathers of Bluegrass: Tribute to 1946 and 1947." The CD, which will be released Tuesday on the Skaggs Family Records label, pays tribute to Bill Monroe's classic band and their definitive recordings.

"Bruce knows that a lot of the fans that come out are bluegrass fans," Skaggs says. "I know that he draws a lot of his own fans. I know that when we're out there we have to make sure that Bruce's fans get what they came for, and Ricky's fans get what they came for. So we try to figure out songs that are up, that are exciting."

Bluegrass fans who remember their history may find the Skaggs-Hornsby collaboration more than a little ironic. In 1989, Hornsby won a Grammy for "Best Bluegrass Recording" for "The Valley Road," a track on The Nitty Gritty Dirt Band's "Will the Circle be Unbroken: Volume II."

The award spawned controversy within the bluegrass community. Fans and artists were angry that a pop artist was chosen over bluegrass nominees who had devoted all their lives to bluegrass music. They also saw red over the fact that the recording included Hornsby's piano -- an instrument purists insist does not belong in bluegrass.

Skaggs feels that the controversy was misguided, and that fans should appreciate Hornsby for the vision he brings to his music.

"[Bruce] gets penalized every time he does something with piano where it refers to bluegrass, and it's just not fair," he says. "It's an acoustic instrument, and he deserves honor wherever he plays because he's a brilliant musician. I think he's one of the greatest musicians I've ever had the privilege to play with."

It's clear that Skaggs appreciates Hornsby's talent and values his friendship. He especially enjoys performing together because every song presents new challenges that test Kentucky Thunder's abilities to listen and respond.

"Bruce don't color in the lines," Skaggs says, laughing. "I bet when he was little that he didn't stay in the lines, and I bet that's followed him all his life. We will work something up and have a plan, but the best-laid plan with Bruce is to watch him and see what he wants to do.

"The spirit may hit him in the middle of something and he might want to break it down to just piano and acoustic guitar, or just piano. So we have to watch that and be ready any time he wants to do that. So everybody's got to listen to the piano and when Bruce is done, then we'll take off. But as long as he's playing, he's grooving and having a big time, and he wants to be there. So that's the most intriguing part.

"And hearing his incredible musical abilities every night. There's no way that anyone could go to a school and learn what he has naturally in his heart. He's truly got a God-given gift, and it's precious."