Rudd stars in Carney’s latest film, Power Ballad, in which he plays a former member of a famous band who has spent the past 15 years living in the city, making a living as a wedding singer.

There are plenty of singer-actors who could have taken on the role, but Rudd — with his ineffable charm — proves more than capable of handling the music. His genuine love of music, rather than any formal musical pedigree, was part of what convinced Carney to cast him: a choice rooted less in technical ability than in instinct.

“The love of music that Paul clearly had from our very first conversation — we didn’t talk as much about acting or films as we did about musical performances that were iconic. If you say a specific ’80s song really spoke to you, then I know we’ll have fun making this film. That was the real connection," says Carney. 

Rudd agrees that something instinctive underpinned their collaboration. “There was always a sense that we would click over music. It’s like any friendship you form: ‘Oh, you like that comedian?’ or ‘We’re both listening to this.’ When you really connect, discover obscure, interesting music together, you just know: ‘This person speaks my language.’”

The film centres on Rudd’s character Rick, who crosses paths with Danny, played by Nick Jonas, a former member of a hugely successful boy band now struggling to establish himself as a solo artist. Over the course of a long night in Dublin, the two musicians drink, bond and jam together, resulting in a piece of music with major consequences for both of them.

The scene feels lived-in and natural, and Carney says he was happy to let the actors take it where it needed to go.

“The meat-and-potatoes stuff was scripted, but then, they’re jamming, they were free to go. I would say, ‘If you don’t feel the script that’s written coming next, just say the approximate version of it.’ I would do anything to make that whole scene feel right over any line of dialogue or plot point, because if that didn’t feel right, the whole film is dead. 

"The film depends on these two guys having this night where they get lost in marijuana, drink, music and creativity, and then it’s a spark for the whole film. So, if the atmosphere isn’t right or believable, we were screwed,” says Carney. 

Rudd quickly points out that Carney’s script did not need any changes, though there was still space to explore its ideas. “The script was pretty airtight. There was never any pressure to do anything except what was written. But at the same time, in the way that John directs, there were moments where he’d say, ‘Let’s jam, like musicians. Let’s see what this is. Let’s throw out what’s on the page and explore.’ That kind of environment fosters real freedom — to just live in the scene and see what happens. Still, it was an airtight script.” 

Rudd is speaking shortly after flying into Ireland from the US, the jet lag written all over his face. Despite the fatigue, his answers are full of energy and he lights up when he talks about his time filming here.

“It was just a thrill — really great. I love this country, and getting to come here for months on end and spend real time was amazing. I didn’t get to travel around as much as I would have liked, but even briefly feeling like a local was awesome.”

It was not Rudd’s first time in Ireland, and he has spoken before about his father, a Titanic scholar, who led many tour groups on pilgrimages to Cork.

“Every time I come here and meet people from here, they’re so nice to me. I know that’s an Irish thing anyway, but I’m from the Midwest — nice recognises nice. There’s a real joy in talking with and meeting people here. 

"And then on top of that, there’s the art that comes from here — the music, the writing, the landscape, the geography, the Guinness, all of it. It just puts you under a kind of spell. It always has for me.”

So when did Rudd first set foot in Ireland? “The first time I came here, I came by myself for three weeks. I rented a car — I was 24 — and I’d always wanted to visit because I’d become really into Irish music as a teenager, and into Irish films. I felt really drawn to it, but I’d never been. 

"So finally, when I was at school, I thought, I can do this — I can just go. And I did. I travelled all over Ireland, met lots of really interesting, great people, did it on a shoestring, and it was magical.” 

Carney can’t help but interject. “I keep seeing a scene where it's two people in West Cork watching

Ant-Man

going, is that that strap of a kid we picked up when he was standing on the side of the road looking for a lift?”

Rudd laughs, saying it’s a possibility, and wonders where that travelling companion might be today. “I was in Galway, I met this kid — his name was John, I think he was from Cavan — and he’d come to Galway over St Patrick’s Day. We ended up spending time together over a couple of days. We kept in touch briefly but then lost contact.

"I have no idea where he is now. I’m not on social media, so I don’t even really know how to reach out to people the way everyone does these days. I often think it would be interesting to run into that guy again.”

It’s impossible not to ask Rudd about moving between the vast scale of Marvel and smaller, more intimate projects like Power Ballad, and where he finds the real creative satisfaction.

“The joy is in doing the stuff that means something to you. I tend to prefer the more intimate work. Marvel has been amazing, but it does feel like its own animal because it’s so enormous — it’s a wild thing to experience. 

"In a way, it can spoil you. If you have an idea, ‘we’ll fix it, we can add this, we’ll throw money at it.’ Everything else I’ve worked on doesn’t have that kind of flexibility or budget. But it hasn’t been the norm for me in my career.” 

For now, Rudd is content to play with the power of music.

“Music can transcend everything. You don’t even have to understand the words. You can hear a song in another language and still connect with it, feel something, remember something. And then lyrically, something can be a bit obtuse, and yet you think, ‘Oh my God, this song is so specific — how does it see into my soul and know exactly what I’m going through right now?’”

• Power Ballad is in cinemas from Friday, May 29