As previously reported, the cast, including Hugh Jackman, Russell Crowe, Anne Hathaway and Aaron Tveit, recorded all of their singing live on set. Earpieces were used to provide the actors with piano accompaniment during the filming.

Academy Award-winning director Tim Hooper ("The King's Speech," "John Adams") utilized this technique in order to harness more realistic performances from his starry cast. Typically, the soundtrack to a film musical is pre-recorded in the months leading up to the filming, with the actors lip-synching on screen.

On Oct. 10, a 70-piece orchestra will gather in London to begin adding the lush orchestral music to the vocals. Les Miserables composer Claude-Michel Schonberg is also at work penning additional symphonic material to underscore the film.

The film, which is due out in December, will also include the new song "Suddenly" for Jean Valjean (Jackman) to sing. Producer Cameron Mackintosh previously told Playbill.com that the song "was something that Alain and Claude-Michel came up with, after a passage in the book, which beautifully explains what happens when [Valjean] takes Cosette from the inn and looks after her. Herbie's written a lovely lyric to it, and we're all delighted how it seems to fit into the film version."

The film stars Jackman as Valjean; Crowe as Javert; Hathaway as Fantine; Tveit as Enjolras; Helena Bonham Carter as Madame Thenardier; Amanda Seyfried as Cosette; Eddie Redmayne as Marius; Samantha Barks as Eponine; George Blagden as student Grantaire; Sacha Baron Cohen as Thenardier; and Daniel Huttlestone as child-hero Gavroche. The movie version of Les Misérables will be in theatres Dec. 7. William Nicholson ("Gladiator," "Nell," "Shadowlands") penned the screenplay. The Les Miz film is from Universal, Cameron Mackintosh and Working Title.