Two pianos, heading to points unknown

When Jason Moran and Robert Glasper stroll onstage to separate pianos Saturday night at Walker Art Center, their first duet will be a boogie-woogie-flavored blues.

After that, anything goes.

"Most of what you hear will be completely improvised," Glasper said with a chuckle. "We barely have set lists. We have points we want to hit, but how we get there, I don't know."

It's not as if Moran and Glasper — two of the most highly regarded and successful pianists in jazz today — don't have an ample catalog of original music at their disposal.

After establishing himself with his highly praised trio the Bandwagon, Moran, 40, has paid tribute to Thelonious Monk and Fats Waller, performed a gently glorious duet album with saxophonist Charles Lloyd, and used his love of dance and visual art as inspiration — including a 2005 piece based on the Walker's collection.

Glasper, 37, has reinvigorated jazz with an infusion of hip-hop and R&B via his Grammy-winning "Black Radio" and "Black Radio 2" albums. His keyboards are all over Kendrick Lamar's heralded new hip-hop disc, "To Pimp a Butterfly."

But Glasper is also thoroughly steeped in the jazz tradition, with his own string of acoustic trio records on the Blue Note label. His latest, "Covered," featuring jazz-inflected treatments of pop songs, will be released later this month.

Moran and Glasper share a hometown (Houston) and an alma mater, that city's High School for the Performing and Visual Arts.

Even then Moran "was a superstar," said Glasper, "so all during my high school years, I was told, 'If you're talented, you can be the next Jason Moran.' "

Both credit their Houston roots for their success. "It doesn't have a stereotypical sound like New Orleans or Motown in Detroit," Moran said. "There's blues, gospel and rhythm & blues in there."

In a separate phone interview, Glasper also cited the city's strong gospel heritage, saying "you get used to music that literally moves through you."

Their first performance of piano duets came at a 2011 concert. Almost three years later, they shared the stage for the 75th anniversary of the Blue Note label, whose first recording featured boogie-woogie pianists Albert Ammons and Meade "Lux" Lewis. To honor that legacy, the pair unfurled a boogie workout that has become their standard intro.

Expect some hip-hop music. The duo have fondly covered "On My Block" by Houston rapper Scarface, along with hip-hop tunes by J Dilla and A Tribe Called Quest.

"During our last tour," said Moran, "I prepared my piano as a drum, coming up with these beats to reference other hip-hop beats moving forward. There are differences [in hip-hop rhythms] both geographically and by decades, from like the late '70s to the late '90s to now. We do think about these things."

But they try not to think too much about a set list before taking the stage. "When we play together, I may suggest a tune literally by playing a chord or a melody and he'll catch on and we'll go with that," Glasper said. "He's marvelous to play with because he has such a big sound."

Moran returns the compliment. "His performance style, the way he adjusts things to the piano, his humor, he has gotten me to do things onstage I normally wouldn't do.

"I know we both can fixate on an idea that could be considered tangential to jazz, but our dedication brings it inside. The good thing about duo piano is there is no place to hide — it's just you and the instruments."