On a late November day in the shadow of London's Albert Bridge, the composer Lorne Balfe is speaking to Billboard and breathing a sigh of relief. The day before, he finally wrapped work on the music for the epic fantasy series His Dark Materials. Scoring the show was a massive endeavor that matched the scope of the big budget BBC/HBO co-production based on the Philip Pullman books, with Balfe recruiting an eclectic cast of musicians (including Red Hot Chili Peppers drummer Chad Smith) and recording in far-flung places ranging from Cuba to London to Thailand to Vienna.

"I wanted to write a musical letter to the creators of the show," he explains of soundtracking the show which stars James McAvoy, Ruth Wilson and Lin-Manuel Miranda. "You begin with sheer fear and you don't sleep a lot. It was a mammoth task and the biggest project I've ever worked on, that's for sure." It's quite a statement from Balfe, a composer who has built a career on a string of gargantuan productions. In the past couple of years alone, he's composed the scores for blockbusters ranging from Mission: Impossible - Fallout and Pacific Rim: Uprising, and collaborated with his mentor Hans Zimmer on Dunkirk and Ad Astra. Most recently, he was behind the music for Ang Lee's sci-fi opus Gemini Man and this December he'll also see the release of the Michael Bay-directed action thriller 6 Underground.

"There used to be a tier system: first it was film composers, then television, then jingles, and then computer game composers were right at the bottom because there was a snobbery about it," he says with a laugh. "Now, everything has turned on its head and every A-list composer is doing video games and television." His Dark Materials was a project he put his heart and soul into as a longtime fan of Pullman's source novels, the first of which was published in 1995. "The fortunate thing about it is that I was able to start early on and I was a fan of the books. I knew the material and lived in it."

Balfe was born in Inverness, Scotland. An ancient city located on the River Ness towards the north of the country, his childhood almost ensured that he'd pursue music as a career. "My father had a residential recording studio up in the Highlands," he says of David Balfe, a songwriter and record producer who frequently collaborated with a range of top acts. "Bands like Ozzy Osbourne's would come in to record and stay there for months on end and my first musical memory was playing on Inner Circle's drum kit when I was about five," he says, noting the irony that he's currently putting the finishing touches on the score for Bad Boys for Life, its de facto theme being Inner Circle's "Bad Boys" hit. "My general youth consisted of people waking up at lunchtime and doing music all day until midnight. To me it was a pretty normal world. I took it for granted and thought it was a normal job."

After a childhood engulfed by music and a short stint as a drummer in bands of his own (a lifestyle he soured on because found lugging his drumkit around too stressful), Balfe eventually began writing jingles as a teen and later fell in as a sort-of intern with Hans Zimmer. At the time, Zimmer was working on films like Pearl Harbor and Pirates of the Caribbean; Balfe used the opportunity to learn as much as he could. "I went to four different music conservatories but was politely asked to leave each one," he remembers. "Hans gave me my training and every second of my professional working career I use what I learned from Hans." Eventually transitioning to writing with Zimmer, Balfe picked up his attitude that he was a filmmaker first and a composer second, with character development taking a front seat to the musical process. "He always talked about the story and the characters rather than discussing the music, which is something I think about continuously to this day," Balfe says of the experience. "Hans also had a way of collaborating, where if he played a piece of piece of music and a director didn't like it, he'd try to figure out what wasn't working."

The lessons Balfe learned from Zimmer are ones he utilized to full effect for His Dark Materials, including the idea of casting certain musicians to bring the personality of his written score to life. "When you're creating music for a film, you have the same tasks as what a casting agent has," he explains of the process. "They'll choose certain actors for a role. The notes are the notes, but it's what they bring to it. It's also a very pop background way of working." With that in mind, Balfe recruited Smith for His Dark Materials, a second collaboration between the two after they previously worked together on the score for 2017's Lego Batman film. "We first connected after I wrote him an email saying, 'I'm your biggest fan will you please drum for me?' I had always wanted to work with him, but the project made sense."

Balfe also recruited acclaimed Berlin Philharmonic member Sarah Willis to handle French horn, as well as Richard Harvey who is considered one of the world's top recorder players. "As soon as I knew who the musicians were going to be, I knew their playing abilities and styles I started writing for them," he says, estimating that his workload consisted of "70 percent thinking, 20 percent writing and 10 percent recording."

With season one of His Dark Materials officially a wrap and season two on its way, Balfe says the most gratifying aspect of embarking on this globe-trotting fantasy musical adventure is watching the show with others and seeing the joy they get from it. "Everybody really knows these books and for them to finally come alive brings a lot of happiness," he says. "So many people work on these productions, they live and breathe it. Even though I'm doing 18- or 19-hour days, I love music and writing and just being able to tell this story."