“This show has been 10 years in the making,” the countertenor Anthony Roth Costanzo said recently.
He was talking about “Only an Octave Apart,” an undefinable event — A staged concert? A revue, maybe? — which he created with Justin Vivian Bond and which runs at St. Ann’s Warehouse in Brooklyn from Tuesday through Oct. 3.
On paper, the two seem to be unlikely collaborators. Bond, 58, is a throaty-toned pioneer of the alternative cabaret scene, both as a solo artist and as half of the duo Kiki and Herb. Costanzo, 39, is a classical star whose luminous voice takes him to opera houses and concert halls around the world. (In the spring, he’ll return to his body-waxed role as the titular character of Philip Glass’s “Akhnaten” at the Metropolitan Opera.)
So it’s not entirely implausible that they’ve ended up together at St. Ann’s, where their set list ricochets giddily from Gluck to Jobim to the Bangles, and the artistic team includes the director Zack Winokur (“The Black Clown”), the fashion designer Jonathan Anderson and the composer Nico Muhly on arrangements.
Bond and Costanzo’s partnership is more organic than most “when worlds collide” projects, which often feel as if an enterprising impresario had pulled random names out of a hat and precipitately pushed the unlucky artists onstage.
“We were seeing each other because we were friends, not because we were intending to collaborate,” Bond said, sitting with Costanzo after a recent rehearsal.
Back in 2011, Costanzo was in the audience at Joe’s Pub for one of Bond’s cabaret outings. When Bond mentioned from the stage that the guest artist for an upcoming performance had just dropped out and there wasn’t a replacement, Costanzo leaned over to a friend and whispered, “Me!”
The friend, the photographer and director Matthew Placek, also knew Bond and made the introductions. Costanzo nabbed the guest spot and prepared a Handel aria, but he was also keen to join voices on “Summertime.”
“You said no,” Costanzo recalled to Bond in the interview. “Then right before the show started, I was practicing it and you were like, ‘All right, all right, we will do it as a duet.’”
The combo was a success. “We sounded so good together,” Bond said. “Of course, that song’s problematic and we can’t sing it anymore, but it gave us an opportunity to see our chemistry onstage, which was really fun.”
So much so that they are back for more, though the initial impetus was rather pedestrian: Costanzo wasn’t sure what to do next for his record company. “I just didn’t want to make ‘Scarlatti Cantatas’ or something,” he said. “I mean, they’re beautiful, but it’s been done.”
Teaming up with Bond provided a creative solution. (And this won’t be their last partnership of the season. They will come together at the New York Philharmonic in January as part of the…