Paul Rudd and Nick Jonas have been cast in 'Power Ballad'.

The duo are attached to the musical comedy movie that tells the story of a wedding singer (Rudd), a rock star (Jonas) and the song that comes between them.

John Carney is directing the movie that has already started filming in Dublin and will be of interest at the Cannes market this month.

Carney has penned the script with Peter McDonald and 30WEST, WME Independent and UTA Independent Film Group are representing domestic sales for the movie while WME are responsible for the overseas rights.

The Irish filmmaker said: "I'm delighted to be working with so many great people. I've been working on this script with my buddy Peter for years, and now Paul Rudd and Nick Jonas are in my kitchen."

Alex Walton of WME added: "We are so excited to bring John Carney's next film to Cannes. John has a magic ability to weave great music into wonderfully engaging and universally relatable stories that make audience emotions run high.

"'Power Ballad' is fun and heartwarming – themes that audiences crave today. His unique vision, coupled with the global appeal of Paul Rudd and Nick Jonas, will give buyers exactly what they're looking for."

Rudd is perhaps best known for his role as the superhero Scott Lang/Ant-Man in the Marvel Cinematic Universe (MCU) and previously opened up about the "horrible" and "restrictive" diet that he had to follow while training for the part.

Speaking on the 'Off Menu' podcast, the 55-year-old star said: "When I was having to train for the 'Ant-Man' movie, and I was on a very restrictive diet, my reward was sparkling water. That’s how horrible that diet was. I was like, 'Alright, I’m gonna have some sparkling water now, I’ve earned it'."