Beethoven composed his “Hammerklavier” Sonata in 1817 and 1818, and afterward he wrote a note to his publishers that read: “Now you have a sonata which will keep the pianists busy when it is played 50 years hence.” (Or so says writer Julian Haylock in the liner notes to the Alfred Brendel recording I own.)

Whether it’s still keeping pianists busy or not, Beethoven’s work has been occupying a certain choreographer lately. Tonight, New York City Ballet presents the premiere of Christopher Wheeldon’s new work, “Klavier,” a piece for 10 dancers set to the Adagio of the “Hammerklavier” Sonata.

This moody, romantic ballet will feature two principal couples – Wendy Whelan with Sebastien Marcovici and Miranda Weese with Albert Evans – along with an ensemble. Off to the left of the stage will be another significant performer: City Ballet’s pianist, Cameron Grant.

Musicians who work closely with dance companies have skills that aren’t easy to acquire. “It’s a unique field because you can’t appreciate what goes on unless you do it day to day,” Mr. Grant told me.

After 20 years in City Ballet’s orchestra, Mr. Grant is that rare breed of musician who understands dance and can collaborate with a choreographer. “Everything we play is totally transformed when doing it for dance,” he said. “You have to do things that make sense with the dance. It’s the two together that make for the experience.”

To ensure that the experience is at its best, the musician and the choreographer must come to an agreement about tempo and pacing before anyone enters the studio. “I had never played the ‘Hammerklavier’ Sonata,” Mr. Grant said. “We listened to a lot of recordings.”

Learning it for the ballet became an evolutionary process for Mr. Grant – just as learning the steps was a process for the dancers. “I’ve played every rehearsal with them. It normally works that way with a solo piano piece,” Mr. Grant said. “You work your way through together. You’re getting more and more solidified in your own interpretations.”

Along the way, choices are made. “[Mr. Wheeldon] created a very passionate pas de deux with Wendy and Sebastien, and the speed of that suddenly picks up,” Mr. Grant said. “If I was too stately, it didn’t work. I had to speed it up.”

Making such decisions by committee can be difficult for a musician, especially if he has performed a work according to his own interpretation in the past. “Oftentimes I do know the music,” Mr. Grant said, recalling when Mr. Wheeldon created “Mercurial Maneuvers” to Shostakovich’s Piano Concerto No. 1. “It was harder for me. I had played that in concert.”

Part of the difficulty is that choreographers may listen to a recording that differs from the way a musician might interpret a given piece. But in this case, it was uncharted territory for everyone. “I didn’t know it, and I didn’t try to get solidified until just [two weeks ago]. I really wanted to let him move it around according to what he needed,” Mr. Grant said.

Such flexibility has developed over time. Mr. Grant started out as a concert pianist; then, a violinist in the orchestra suggested the ballet. “I was doing the normal freelance musician thing,” he said. “They were looking for another pianist to join the staff. I thought a regular paycheck might be nice.”

He began part time with the ballet and found the process difficult until he committed to it. “What really helps is doing ballets from the beginning – either having somebody choreograph or you learning it while the dancers are learning it,” he said.

“Sonatas and Interludes” taught him that lesson. “I got to learn every step,” he said. “Those types of situations where I would be learning really taught me a lot. If you pay attention and watch, you see how the dance and music hook up. I just love it, and now I’m much better equipped to do it.”

In performance, the ability to make the music and dance happen at the same time requires some quick glances up from the keyboard. “I look up all the time. It depends on the ballet,” Mr. Grant said. When it’s something fast, and I’m in my own world, I know the tempo that they need. But in something like ‘In the Night’ or this, I’m checking in regularly.”

What he’s looking for are the details that unfold in live performance. “Maybe they’re rushing, or I’m behind. It’s nice to have it sync up. [A choreographer] has specific places where he wants certain steps,” he said.

And when there are no other musicians involved – and no conductor – the responsibility is entirely on the pianist. “It’s nerve-wracking in a way, but there’s a comfort in that, too. You don’t have any other variables in that. You have all the controls in front of you,” he said.

As for the dancing in “Klavier,” the pianist says there’s good stuff ahead. “It’s a beautiful piece.”

And he’s not alone. “It has a little bit of flair of drama. It’s a sort of moody and dark feeling, which is my favorite,” principal dancer Miranda Weese said, adding that the costumes suggest modern renaissance. “They’re very beautiful.”

Surely the music will be, too.

pcatton@nysun.com