Breaking with tradition is a risky move in ballet. But with its new production of “Romeo & Juliet,” choreographed by artistic director Peter Martins, New York City Ballet is taking that risk — in more ways than one. Starting May 1, audiences will see fair Verona and some characters interpreted in a new direction. The title roles will not be not held by principal dancers; instead, they will be danced by some of the company’s youngest talents. And those up-and-comers will be doing something with which the dancers of NYCB — who open their season tonight with George Balanchine’s neoclassical, plotless ballets — have comparatively little experience: acting.

Although the foundation is Shakespeare’s play and Prokofiev’s music, Mr. Martins’s “Romeo and Juliet” offers something unexpected at almost every turn. By far the most important aspect of this production is that a new generation of City Ballet dancers has the opportunity to work on narrative roles and to learn from Mr. Martins, who grew up in the classically oriented Royal Danish Ballet. There are few roles in the City Ballet repertory that give dancers the chance to act or emote — let alone sword fight — as much as they will here.

“Romeo and Juliet” is even more unusual for this company in that it is entirely made from scratch; there are no Balanchine passages, as in “Sleeping Beauty,” or Petipa must-haves, as in “Swan Lake.” Which is not to say that the work entirely lacks the Balanchine vocabulary or Robbins-esque groupings. But Mr. Martins started with a clean slate. If there are familiar elements, it’s because he chose to include them.

Also new is the thinking behind the casting of the roles of Romeo and Juliet. Both roles are typically performed by mature dancers who have logged professional and personal experience, on which they can rely to communicate the characters’ emotional extremes. But the two lead roles, as per Shakespeare’s instructions, are written as young teenagers — as young as 14 — and Mr. Martins has cast the title roles with an eye toward authenticity rather than expertise. The opening night cast will feature Sterling Hyltin, a soloist since March 2006, and Robert Fairchild, a member of the corps de ballet. Indeed, all of the Romeos — Sean Suozzi, Seth Orza, and Allen Peiffer — are in the corps de ballet. Their respective Juliets are Tiler Peck, a soloist since December 2006; Kathryn Morgan, a corps de ballet member, and Erica Pereira, who at 18 years old is an apprentice to the company.

Such coltish talent may not result in the heart-rending depth of a Margot Fonteyn-Rudolf Nureyev partnership. But it may lead to some bracing reality. Those fresh baby faces and teenage bodies can emphasize Romeo’s dreamy impetuosity and Juliet’s brash responses. Leave it for the choreography to communicate the throes of emotion, Mr. Martins’s decision implies. These young adults make for some ballet vérité.

Longtime NYCB watchers may be amused to see some of the company’s principal dancers in supporting roles. The dowdy role of Friar Lawrence will be played by Nikolaj Hübbe — a hunky dancer who joined the company as a principal in 1992 and is perhaps best suited to his other holiest of roles: “Apollo.” Lord and Lady Capulet will be played by Darci Kistler — a principal since 1982 — and former principal Jock Soto, who came out of retirement for this theatrical role. As for the nurse, no chubby, nun-like character is she. As some lines of the play suggest, the nurse is unabashed by sexual innuendo — and in this ballet, played by Georgina Pazcoguin, a slim, pretty member of the corps de ballet.

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The first steps toward this production took place not in New York, but near Copenhagen, Denmark. Mr. Martins traveled there with stage manager Perry Silvey for meetings with the Danish abstract painter Per Kirkeby, whose aesthetic of jagged natural forms sets the visual tone for the new ballet. Mr. Kirkeby and Mr. Martins previously collaborated on a production of “Swan Lake” that made its New York premiere in 1999.

While working in Mr. Kirkeby’s rustic home, the trio refined a vision for a minimal set that would free the ballet from too much period realism. In the end, the group chose four original paintings — as opposed to painted scenes that connect to stage architecture — as backdrops, as well as a scrim that can change the audience’s view of those paintings. The paintings were transposed onto the giant drops at a facility in upstate New York; Mr. Kirkeby then visited the drops to add his own touches.

As for architecture on stage, “Romeo & Juliet” requires that certain scenes take place in specific rooms. To accommodate the narrative while maintaining a sparse approach, Mr. Martins relied on stagecraft inspired by one of Balanchine’s narrative ballets. In the 1929 “Prodigal Son,” a single prop — a long wooden rectangle — is used throughout the story as a table, boat, fence, a monolith, and more. In “Romeo and Juliet,” that idea becomes one piece of scenery, rather than one prop, that can change shape and move onstage as needed. “We really needed a bigger piece that could change into the ballroom, balcony, bedroom,” Mr. Silvey said. “In the second act, it’s the friar’s chapel, then the tomb. Everything is contained.”

This one unit of scenery is painted to look as if it is built of stone, and its movable parts are arranged in a variety of ways. In Act One, the panels of the unit are set to look like market stalls. When reassembled, a set of staircases slips out of the side and the unit becomes Juliet’s balcony, with her standing on the top of the structure. What allows the ballet to move quickly is that these changes take place onstage — courtesy of stagehands inside it — as the music plays on. “Peter choreographed the scene changes to keep it seamless,” Mr. Silvey said.

The unit is painted with a design created by Mr. Kirkeby. Jagged black lines and shades of grey suggest heavy stone. On a recent visit, the painter went back over each panel of the unit adding more paint to increase the illusion of the dark stones and old crevices. “I wouldn’t like it to be perfect. They’re stone slabs and joints,” he said, dabbing more black into to an already black line.

The backdrop paintings he created for the ballet incorporate colors in sharp contrast — a reflection of the conflict at the heart of the story. Mr. Kirkeby’s take on how his paintings connect to the story is clear: “It’s a tragedy. It gets darker and darker.” But he is adamant that his role is a collaborative one. “I’m not making an exhibition. It’s in service to something else,” he said.

That “something else” is a streamlined ballet that keeps the action moving at a hurtling pace. Repetitive portions of the score were cut. Ancillary action, such as the flirty harlots with their divertissements, is limited. And because the scene changes take place in full view of the audience, there is no need for time-consuming stopping and starting or multiple intermissions.

It has been 10 years since Mr. Martins created a new full-length narrative ballet. (“Swan Lake” had its premiere with the Royal Danish Ballet in 1996.) That production, too, was untraditional in that it stripped away many conventions and added more dance — all of which enhanced the experience of seeing ballet. It stands to reason that the past decade has given him time to refine his vision for classical works at NYCB. And in the end, Mr. Martins’s risks may prove well worth taking.