Composer Rachel Portman has underlined the period romanticism of Emma, heightened the drama of The Cider House Rules, and lent ethnic perspective to Chocolat. Now, she'll convey the world of a mysterious boy prince from a faraway star and the downed pilot who encounters him. The difference, though, is this: The Little Prince, Portman's take on Antoine de Saint-Exupéry's famous children's book, is an opera, not a film.

"For most of my grown-up life, I've written music that tells a story," Portman says, referring to her two-decade career scoring television and movies, first in her native England, lately in Hollywood. "But I've never had the chance to express a character vocally. I've always wanted to write an opera for that reason, to move a little closer to the telling of a story."

The stories that Portman helps to tell on screen are, for the most part, already told by the time a film reaches her and her instrument of choice, the piano.

"A film is already finished when I score it," she says. "My job is to respond to what I see. Film scoring is fascinating work, but it's a little like adding a brushstroke to an already completed canvas. The Little Prince is an opportunity to paint the whole picture."

The novel was musicalized on screen in the 1970s by Lerner and Loewe in the final collaboration of the My Fair Lady-Camelot team, but it failed to catch on as a lasting transmutation of the novella. Vol de nuit ("Night Flight"), the other of Saint-Exupéry's two best-known books, has been repeatedly set as an opera, but never with success. Portman went for the current project as a chance to help clarify and illuminate the haunting, mythically flavored tale.

"The Little Prince is all about how grown-ups forget their childhood and complicate things," she says. "It's about the need to return to simplicity and honesty. As a child, I read it and I remember the tenderness of it. But it's actually quite difficult for children to understand. I don't think I got anything at the end of the book except pangs of sadness. Then you return to it as an adult and suddenly realize what it's about."

Portman intends her music to "color the emotions" of the characters' words and actions, and help convey to both children and adults in the audience the truths of the story. It's especially important to her now, she adds, since the children in the audience will almost certainly include her own: Anna, 7; Giulia, 4; and Niky, 3.

At 42, Portman is widely known for her string-rich, romantic sound in such films as Only You and Emma (which won Portman the first Oscar for music ever awarded to a woman). Nonetheless, she's taken on a host of other genres, including screwball comedy (The Road to Wellville) and combat (Hart's War). And in 1997 the composer created songs with lyricist Don Black for Disney's home video Beauty and the Beast: The Enchanted Christmas, which is the closest she has come to writing for the lyric theater, until now.

Portman is hardly alone among composers in getting a relatively late start at opera. Janácek was nearing 50 when Jenufa, the earliest of the operas he is today known for, was successfully produced. Before that, he was regarded largely as a choral writer. Johann Strauss Jr. was a bandleader and inventor of waltzes for decades. When the Viennese were mad to find an Austrian who could compete with the success of French operettas, he turned to the genre and wrote Die Fledermaus.

The biggest change Portman has had to face in switching genres is that of taking on responsibility for dramatic pacing. A composer's score is a kind of pre-fabricated stage direction that dictates the tempo of the action as well as the music. "The momentum and the dramatic pacing are incredibly important," she declares. "That's the first thing you realize when you shift from film to opera. As the composer of an opera, you are there to provide everything, and you must at all times keep in mind the dramatic motion of the piece."

Portman's music will follow a lyrical line, rather than cradle itself in the arms of its orchestration. Unlike her film music, Portman's Little Prince will put the vocal utterances of the characters front and center. Even so, she says, her background has come in handy:

"It is useful to have a life's experience writing dramatic music."

Ken LaFave writes about classical music and dance for The Arizona Republic.