It’s a Tuesday afternoon in late March on the Newman Scoring Stage at 20th Century-Fox. Harry Gregson-Williams, looking a bit haggard after having been up most of the night finishing the music of “X-Men Origins: Wolverine,” stands before a 40-voice choir as they prepare to sing — in the strange-sounding Old Icelandic language — stanzas from an ancient Norse poem that will underscore the film’s dramatic opening.

“Let’s try one a little hushed,” Gregson-Williams tells them. “There’s supposed to be something inevitably tragic about it,” he adds. The lights dim, the red “recording” light is illuminated, and far behind the choir, the opening title sequence of “Wolverine” begins to play silently on the bigscreen.

The composer conducts the singers (20 men, 20 women) to a music track that was created in his studio but will, by the end of the day, be mostly replaced by a 78-piece orchestra. They complete a satisfactory take, and Gregson-Williams praises them — “You’ve got the spirit of it” — while also urging nuance in their performance: “Not too coarse. It should be really sweet; musically we are saying one thing while we are seeing another.”

Gregson-Williams, a veteran choral director from his days as an educator, conducts (with his hands, not a baton) expressively, with full, round gestures, leaning into the more dramatic moments. He moves one headphone off his ear so that he can hear the choir sing in the cavernous Fox stage while still listening to the backing track.

A few minutes later, the composer enters the booth where engineer Joel Iwataki has been monitoring recording levels while studio execs hover. He cautions director Gavin Hood that they are listening to a very rough mix. “Harry,” the animated Hood responds, “I’m not only not worried, I’m pleased and excited!”

Two hours later, the orchestra begins a 90-minute session to record cue 1M2, the 4½-minute “Logan Through Time,” which will incorporate the choral elements already recorded. After a rehearsal, Gregson-Williams addresses the strings: “Quite spiky, lots of rosin,” he says. “Everybody, crescendo through bar nine, big accent on bar 10.”

This time, the composer conducts with his pencil, moving around the podium as he gestures to each section depending on the musical emphasis required. The music is powerful, sometimes dissonant, a bit sad, as the viewer is introduced to Wolverine (Hugh Jackman) and his brother (Liev Schreiber). The mood is mostly serious, as this is not only the final scoring session but also the all-important opening of the film.

During a break, director Hood talks about Gregson-Williams’ role in scoring “Wolverine”: “Harry’s challenge is to give us operatic scale, but also keep it intimate and human. Harry’s music has a kind of muscular confidence and strength that is very useful for the action, but he also has tremendous soul.”

Hood emerges from the booth at the end of the session, hugs the composer and thanks the orchestra with three words:

“It’s frigging brilliant!”