Our exclusive premiere of the psych-thriller's trailer features a clip of Weezer's forthcoming new song, 'California Snow.'

You probably got to know Patrick Stump from hearing him sing Pete Wentz's lyrics. In that, he's a rare case: a lead singer from a massively successful rock band who's not recognized as the group's frontman. Stump's childhood friend was always the prettier Fall Out Boy, the one who pep talks the crowd in between songs, the one who writes the lyrics -- or as he'd call them, "weapons in the form of words." Together, they're among 21st century pop's most successful symbiotic partnerships: the unflinching, soulful vibrato and the unflinching social media presence.

Stump does a lot of creating outside Fall Out Boy, and if his role in the band is often understated, his work beyond it is a near mystery. His latest project was writing the often-ominous score for Spell, a bizarro thriller set in the wilds of Iceland -- which also happens to be the first feature film from Crush Pictures, a film extension of management company that's worked Fall Out Boy since 2002. You'd think it would have been some inside job, but Stump reveals Crush actually didn't seek him out until he insisted, and after production was already well underway: "They said they were looking for a composer for a movie and I just go, 'Yeah, I’m a composer.' It was this right-under-their-noses thing -- “Oh yeah! Weird, you are I guess!”

In Spell, Stump is tasked with capturing the frenetic inner monologue of Benny (Barak Hardley), a troubled 30-something American on a surreal journey through the Icelandic wilderness following the sudden death of his fiancée. Sparse, icy, and often jarring, the suites Stump wrote for Spell sound nothing like Fall Out Boy, though the film does contain one familiar nugget for fans of his solo career: a retro-sounding soul song, written and sung by Stump, which plays a crucial role in the plot. It also features the voicework of Weezer frontman Rivers Cuomo and a brand new song from Weezer themselves. As he got acquainted with the script for his cameo as Benny's doctor, Cuomo tweaked an unreleased demo he had lying around to fit Spell's vibe, which now appears in the end credits as "California Snow." (The just-announced song is set for proper release tomorrow, but you can hear a snippet of it in the Spell trailer, premiering exclusively below). And keeping it all in house, Spell is the directorial debut from Crush's Brendan Walter, who's directed numerous Fall Out Boy and Weezer videos.

In Billboard's recent chat with Stump, we began covering the Spell process, and wound up zeroing in on the passion that's driven him since childhood: wanting to write music, but also wanting to do goofy impressions of SNL and cartoon characters, which actually led him to getting taken seriously as a composer. The film debuts Sept. 23 at the LA Film Festival; below, find our career-spanning Stump Q&A and the brand new Spell trailer below.

How did you wind up scoring Spell?

I’ve been shouting from the rooftops that I wanted to score! The band’s been around 17 years; I think for 15 of those I’ve been, “Hey, I’d love to score! Just so you know, I like composing!” When they started the film, it still hadn’t gotten back, even internally, that I was doing this. I kind of fell into it.

What finally happened was I scored the Incredible Hulk Roller Coaster at Universal Studios Orlando. I kind of bluffed my way into doing it with a full orchestra. I was like, “Can I do that?” And they were just, “Yeah sure, whatever.” They really gave me the keys to the car, or the keys to the ride, in this case. The fact I’d composed with a whole orchestra -- I did it by myself, without an assistant -- then I worked on a film called Gnome Alone, and one called Changeland. So by the time they were working on Spell, I had already done a couple films, and weirdly, Crush hadn’t caught up to it. So they said they were looking for a composer for a movie and I just go, “Yeah, I’m a composer.” It was this right-under-their-noses thing -- “Oh yeah! Weird, you are I guess!”

I got on a call with Brendan [Walter]… You know it’s weird because we’re buddies, we’ve known each other for years, and we’ve worked on stuff together, but this is completely different. I’d never worked with him as a film director and he’d never worked with me as a composer, so we were kind of feeling each other out in the conversation and we were like, "This is gonna be great." In fact, he and I have worked on a lot of pitches for shows since then. I’ve been on reserve for him on anything he’s working on.

For those who don't know much about scoring a film, what's the process like? Do they give you the movie minus the score, and ask you to set music to it?

Yeah, pretty much. Every composer and every filmmaker does it differently. Sometimes there’s what’s called a temp, where they use music from other movies they don’t have the rights to, to demonstrate what they would want. For example, if you had a big action scene, you could cut in a piece of the score from Terminator, as an example of what they’re looking for. In this case, there was a light temp with some stuff, where he had some ideas of what he wanted, but it was fairly open. I had free reign in a lot of places. There’s a few in particular -- some of the really dramatic stuff -- that I was really able to play around with and imagine what I wanted.

I always want to be melodic, have a melody that you hum. I’ve been making pop music for 17 years; this is drilled into you. In this film, a melody is sometimes a hindrance for the emotions and storytelling. So I was trying to find ways to really underplay it, be more minimalist. It kind of goes against my nature. There are one or two Icelandic pop songs in it, but all the other music you hear in the film is me.

You've worked with Brendan Walter on a bunch of Fall Out Boy music videos. What was it like collaborating with him on his first film?

I’ve scored a few films and some shows; I’m not an old pro but I’m comfortable as a composer now. He’s the first director -- or anyone involved in production I’ve worked with -- who’s also a pretty great musician. It was one of the easiest I worked on because there were just language things… He was so quick to describing what he meant. It’s one thing to describe, say, chords: “Why don’t we go to a minor here?” But it’s another thing, not just knowing the nomenclature, to also know the purpose behind stuff. “Why don’t we try something like this here?” He has a very clear idea of what he wanted and it allowed me to just play.

It’s such a strange film, especially with the music, what I did. He let me go to some really weird places. Like the old soul song, the piano polonaise [from another pivotal scene]. There was this one transitional cue where he was like, “I really want it to sound like this old K-Mart commercial.” What about it? “Everything! I want it to sound like the tape is all broken and old.” So I got to play around with the sound design of that, making something feel like you found it on a cassette. It also plays into the surroundings of the film, this insular community the character is entering into.

What else are you working on?

I’m working on a series of shorts for a cable TV network and a six-episode documentary science series. And I have a short film coming out called Wonderland. I’ll probably start recording that in the next couple weeks. I’m busy!

Once Fall Out Boy’s tour wraps, what’s going on for you? What are you excited about?

I’ll be excited to go home, see my kids and stuff. Professionally, the scoring thing is becoming, in a lot of ways… I did the solo thing, and I loved making that record [2011's Soul Punk]. But now as a composer, I’m like, “Oh, this is my solo record.” This my real solo record, writing music for films, TV, and stuff. I get to experiment with everything. In Changeland, I had to learn a lot about South Thai music. In Spell, there’s a hint of Icelandic influence. It’s fun to have those challenges. That’s exactly the kind of nerd I am; I want someone to go, “Okay you have to learn to play an oud, go!”

Solo Patrick Stump, the soul singer, is that a thing of the past?

It’s not formally done for me. It’s more like... So I sing in Spell and I sing a little bit in Changeland, so I kind of get it out in those contexts. I have Fall Out Boy and I’m really proud of Soul Punk for what it was. I’ve said stuff like this before and I mean it -- I don’t ever want to ruin something just for the fun of doing it. I wouldn’t put out another solo record unless I had something I really, really needed to say. Whereas film, they need the music. So there’s that need you fill. It’s really rewarding to help someone tell their story.

Beyond the current tour, is there Fall Out Boy stuff on the horizon?

I don’t know. Yes, but what, I don’t know. To be entirely honest, none of us had any idea when we did [2013 album] Save Rock and Roll that it would even take as strongly as it did. We did it because we wanted to and it was fun. But there were no business expectations. There was no one going, “So when’s the new Fall Out Boy record?” It was a very big surprise for people when we did a record at all. I had no idea that we could be three records in from that, playing Wrigley Field and all this stuff.

And now people are asking when we’re gonna do another record. That’s a weird sign. I think our best stuff is when no one saw us coming. So I don’t know what’s next. But I definitely wanna wait until we have a surprise for people. That’s when we’re at our best. When you can count on us, it’s too easy.

Sounds like “when inspiration strikes” is a way to put it.

Yeah, exactly. I’m really proud of what we’ve done so far. And I have ideas for us. But it’s that magic thing of when Pete has an idea, which works with my idea, which works with Joe’s idea, which works with Andy’s idea. When we all get together, that’s something interesting. If you just have one idea, don’t bother. That’s kinda where we are.

If Pete was writing lyrics for your Spell music, what would they be like?

I have no idea. I really don’t. I think the character is so different than Pete’s natural voice. That’s another thing that was really fascinating for me. I have a really hard time speaking my feelings in music. I write them musically. I compose the music and I can express so much of what I think and feel in instrumental settings. But if you ask me to put it into words, especially in the poetic form of songwriting, it’s really difficult for me. There’s something really cathartic about writing for a character. So for Spell, I’m kind of writing as that character’s internal monologue. So on some level, I’d be like, “No Pete, let me have this one.”

You co-wrote a couple tracks on Blink-182’s last album, 2016’s California. Have you contributed anything to the new album they’re working on?

I haven’t. I’ve been a little off the grid of co-writing for a while. That was a really great experience and I’m really amped about what Blink’s been doing but there’s also a thing… I really respond to being needed, and someone needing the help. That makes me so happy as a musician. That’s why film is great -- they need the music! Blink knows how to be Blink. They don’t need my help.

And you were in the hip-hop hooks game for a bit!

Yeah, it’s been a while, but I was playing around with that! A lot of my weird side projects… it’s hard to describe, but they all lead me here. I’m something of a failed actor; that helps me a ton with scoring. And the stuff I’ve done in hip-hop production; that really helps me with scoring. Even working on Fall Out Boy music videos has helped me with scoring. I was watching an interview with Hans Zimmer... He was saying that every film composer also carries with him some failed film director, or they wanted to write a script and couldn’t do it. But they got the music part.

Do you have any other creative projects that people don’t really know about?

Periodically, I’m a voice actor. That’s just the most fun. Like -- look, I’m five-foot-four. I’m a cross between Bruce McCulloch and Rick Moranis. And I’m a singer in a rock band. If I’m called into casting it’s like, "You’re a rock guy… oh wait, you’re not a rock guy." You wouldn’t cast me as a rock singer. No one knows what to do with me. But with my voice, I can do all these different characters. I actually audition pretty constantly for stuff. I have a character on Star vs. the Forces of Evil. I’m periodically on Robot Chicken.

See these things all feed each other -- I composed Gnome Alone because I’d gotten a voice role on it. I voiced these gruff, little gnome characters; you’d never guess it was me. I was in the booth recording voices and one of the producers comes in: “Hey, I heard you just scored the Hulk ride at Universal. Would you want to compose for this movie?”

Where do you trace this back to -- wanting to use your voice for art?

No one knew I was a singer. I didn’t know I was a singer! When I told my parents I was taking a semester off from college to play in a band, they were like, "What do you play?" When I told them I sing, they were like, “Really?” [Laughs.] They’d never heard me sing. I don’t know where it came from, but I think it was being a little kid watching cable TV and learning to mimic it. I watched a lot of cartoons. Now I’m armed with all this stuff for scoring because I’m a cartoon nerd, knowing all these voices. I got to sing as Batman in The Lego Batman Movie. That’s a neat way to bridge those gaps: character acting, music for film, mimicry.

Didn’t you try out for Fall Out Boy as the drummer?

In any other band I’d ever been in, I was the drummer. I’d never sung before.

But you’re… really good! Why weren’t you singing and what got you doing it?

It was blind luck. I was doing silly voices first. Singing was just another silly voice for me. I would do impersonations of SNL characters and stuff. Singing was just an extension of that. I would do impersonations of singers. I never thought it was an art form I had access to. Singers were real singers. I was just some smartass being silly with my voice.

At the core of all of it, I’ve always just wanted to write music. That’s why I’m doing film, Fall Out Boy, any of it.

As a drummer, for whatever reason, no one will ever let you write music: “Drummers don’t know that stuff.” I’m like, “Yeah it requires a lot of coordination, a lot of music theory, but yeah, okay!” I just wanted a band where they would let me write music. I was showing the band (which would become Fall Out Boy) what I'd written, and as a necessity, I was singing it to them. They were like, “Oh, you should sing.” I was like, “Okay, cool! But is this song okay?”

And here I am.