Paul Rudd gets a chance to realize his musical dreams in ‘Power Ballad’

“It kind of has to work,” he remembers saying. “We’re hinging this thing on it.”

Luckily, director John Carney and musician Gary Clark were working on it.

The result — “How to Write a Song Without You” — becomes a point of contention between Rudd’s character, a wedding singer, and Nick Jonas's, a former boy band standout. The song they create becomes a big hit, but the wedding singer doesn’t get any credit.

To make sure it measured up, Carney relied on experience. He and Clark have worked on four projects, “and I think we kind of finish each other’s sentences musically,” Carney says. “We both know where we want to go with these things … and it was Gary’s great lyric. He was hit by that nice little poetic moment where it’s like the older we become, we’re not writing songs for people anymore because we’re married or we have kids and we have mortgages to pay. It’s our job.”

Because Rudd’s character sees himself as a journeyman, he doesn’t think about writing hits but covering others’.

Those songs, Rudd says, were particularly intriguing.

“Early on, it’s like, ‘What would a wedding band sing?’ Well, ‘Celebration.’ I think I’ve heard that at every wedding," he says. "And it was kind of fun to write a list of songs that we might do, that would work.”

Carney recorded many of them, even though they don’t appear in the film. “And that was a blast,” Rudd says.

While he doesn’t consider himself a singer, “I like to play music,” he adds. “I like to sing in the way that everyone kind of does. I’m not the kind of guitarist that is so proficient that people go, ‘Oh, man. Play some guitar.’ No one’s ever asked that.”

Thankfully, Carney “directs like a musician,” Rudd says. He helped the veteran actor through the hurdles and didn’t hesitate to toss things that didn’t work.

“A musician may come up with a great chord progression … and the rest of the band’s like, ‘Let’s flesh that out. Keep going.’ That’s what it’s like working on a John Carney movie,” Rudd says.

Nick Jonas was collaborative as well.

“The first scene we shot was the first scene (that we were in). It was also what was happening in real life,” Rudd says. “I’d never met Nick before we worked on this. But we fell into it pretty easily.”

Those moments of creation, he says, fulfilled a fantasy.

“We’re just making music and I’m doing it with an actual musician," Rudd says. "So, it was just kind of fun.”

Rudd says he didn’t need to consult musicians to play the band’s lead singer.

“I prepared my entire life imagining, fantasizing about doing this," he says. "I was a little kid, like 4 or 5 years old, playing music and standing on my bed, singing into a hairbrush.”

The trick to making it work on screen was to “jump in and hope for the best," he says.

“Instead of letting the fear of doing something that’s a bit outside my lane overwhelm me, I try to take the opposite approach," Rudd says. "Everything is daunting until you decide, ‘this is fun,’ and you just jump right in.”

While Jonas sings the power ballad in the film, Rudd gets a handful of covers. Singing them made him appreciate the work of those who do it for a living.

“There’s a lot on a wedding band’s shoulders,” he says. “This is the most important day of (the couple’s) lives up to this point, and with that comes responsibility.”