Sitting down with composer Simon Franglen to talk about Avatar: Fire and Ash felt a little surreal – in the best way possible. This is a guy whose fingerprints are all over modern cinematic music, and now he’s carrying the torch for one of the biggest film franchises of all time.

Franglen isn’t just composing another sequel score here. He’s helping define the emotional backbone of Avatar’s next chapter – one that’s bigger, darker, and more immersive than anything we’ve seen in Pandora so far. And after talking with him, it’s very clear: this score is a labor of love, endurance, and obsession.

From Falling in Love with the Studio to Scoring Cinema History

Simon Franglen knew early on that music – and specifically the studio – was where he belonged. He even wrote to the BBC at just thirteen years old asking how to become a record producer. That passion eventually led him to work under legendary composer John Barry, contributing to films like Dances with Wolves and Chaplin.

That experience was pivotal. It’s where Franglen truly fell in love with the relationship between image and music – how sound can elevate storytelling in ways nothing else can. That philosophy carries through every part of his work today.

Entering Pandora with James Horner and James Cameron

Franglen’s journey into Avatar began in 2009, when James Horner invited him to see early footage from the first film. Five minutes in – Jake Sully in the glowing forest – and Franglen was hooked.

That collaboration turned into a full year of work on Avatar, with Horner handling the orchestral themes while Franglen focused on rhythm, texture, and the unique sonic identity of Pandora itself. Think of the glowing forest sounds, the alien textures, the pulse beneath the orchestra – that was Franglen’s world.

After Horner’s passing in 2015, Franglen naturally stepped into a larger role, eventually becoming the lead musical voice for the franchise moving forward.

Fire and Ash Is on a Completely Different Scale

If Avatar and The Way of Water felt big, Fire and Ash makes them look almost intimate by comparison.

Franglen described it best, “It makes the other two feel like small family dramas. The scale of this one dwarfs anything you’ve seen before, and it’s not just the story, it’s also the visuals.”

Simon has been living with this film for over seven years, he wrote the first piece of music for Fire and Ash in February 2018; the full score contains 1,907 pages of music.

That’s not just a score – that’s a marathon.

Grief, Fire, and Emotional Extremes

One of the biggest musical challenges in Fire and Ash is its emotional range. The film opens in grief – two parents trying to process the loss of a child. That meant restraint, intimacy, and vulnerability in the music. Franglen talked about resisting the urge to “overplay” those moments, letting silence and subtlety do the work. Then the film explodes outward. Fire. Ash. Massive action. New clans. New cultures.

And because this is a James Cameron film, the action is absolutely off the charts. Franglen is quick to point out that music isn’t just about making action louder – it’s about helping the audience track emotion, geography, and story momentum when chaos is happening on screen.

Working with James Cameron: One Vision, One Voice

One of the most fascinating parts of our conversation was how Franglen described working with James Cameron. In short: there’s only one opinion that matters. No producer interference. No committee. Franglen writes until he feels it’s right. Then he plays it for Cameron. If Cameron feels it, that’s it – it’s locked. That trust also allows Franglen to push back creatively. One of the defining musical ideas for the Ash clan emerged when Franglen explored an alternative approach to Cameron’s initial concept, introducing bold, driving Mongolian string textures that immediately resonated.

Cameron’s response?

“That’s it.”

Inventing the Sound of Pandora

For Avatar: Fire and Ash, Simon Franglen wasn’t just composing music – he was helping invent culture. One of the clearest examples is his work on the Wind Traders, a seafaring Na’vi clan whose music required instruments that could plausibly exist on Pandora. Rather than leaning on familiar Earth sounds, Franglen designed entirely new instruments based on the clan’s anatomy, materials, and relationship to the sea. His sketches became full-size, playable instruments performed on set and woven directly into the score – meaning what audiences see on screen is exactly what they hear.

That commitment to authenticity extended across the film. Working alongside artists and designers in what the team called the “Culture Club,” Franglen helped ground each fictional culture in real-world human history. Chants are performed in Na’vi, vocal techniques draw from indigenous traditions, and nothing is arbitrary. As James Cameron insists, the world has to feel real – and the music is a vital part of that realism.

Fire, Ash, and the Theatrical Experience

When asked to name the cue that defines the score, Franglen points to “I Am the Fire,” a six-minute piece that acts as the film’s emotional turning point. Combining experimental orchestration, vocals, electronics, and immersive spatial design, it’s music built to be felt as much as heard. Franglen strongly recommends experiencing the score in a theater – particularly in Dolby Atmos – where the scale, movement, and physicality of the sound become part of the storytelling.

While Fire and Ash is largely new material, Franglen carefully carries forward Avatar’s musical DNA, with subtle echoes of earlier themes and the spirit of James Horner’s work. The process continued right up to the finish line, with Franglen making changes just days before final delivery – the reality of shaping a film at this scale.

More than anything, Franglen hopes audiences feel the music as an emotional heartbeat – not background, not wallpaper, but something essential that completes the journey.

Avatar: Fire and Ash arrives exclusively in theaters on December 19, 2025.