Eve Hewson felt nervous to sing in “Flora and Son,” a charming movie about a struggling young mother in Dublin who attempts to connect with her troubled son through music. But that doesn’t mean she wanted advice from her dad, U2 frontman Bono.

“I’ve learned so much from him, in terms of life presence, stage presence. But I didn’t ask him for help,” Hewson says at the Variety Sundance Studio presented by Audible. “He offered, and I was like, ‘No thank you.’ He’s, like, a really good singer so I was like, ‘No, no, no.’

In the movie, which was directed by John Carney and premiered at this year’s Sundance Film Festival, Hewson’s character Flora is new to the world of singing and songwriting. After she finds a discarded guitar, she connects with a Los Angeles-based online guitar teacher (played by Joseph Gordon-Levitt) and finds purpose through the power of music. By the end of the feel-good film, she gets the confidence to perform in front of crowds.

“I grew up musical, so it was kind of natural for me,” she says. “Being on stage, being the front person, I was kind of into it.” She remembers telling her father, “I see why you like this. This is kind of fun.”

Along with catchy tunes, “Flora and Son” is filled with biting Irish humor. There’s a big difference, the mostly Irish cast of Hewson, Orén Kinlan (the titular son) and Jack Reynor (who plays Flora’s ex) admits, between comedy in Ireland and America.

“It’s very dry. It’s very cutting. We like to go below the belt,” Hewson says, “American is more toilet humor. Let’s talk about sex and poo.”

Reynor chimed in, “We like to do self-deprecation.”

Gordon-Levitt, the film’s token American, couldn’t help but agree with his castmates. “In American comedy,” he says, “audiences want to know when they’re supposed to laugh.”

Carney, the Irish filmmaker best known for “Once” and “Sing Street,” says there’s a real demand for feel-good stories.

“Remember how much joy and mirth you had as a kid? It goes and goes as you get older and life,” Carney says. “There’s a need that’s missing from very dark stories that are dealing with how fucked up the world is in the moment.”

Those kinds of films are important as well, Gordon-Levitt says. But there’s something to be said about channeling a little positivity.

“It’s easy to get attention and captivate an audience by being pessimistic. The best way to get everyone’s attention is to run over the hilltop and say, ‘We’re all going to die!’ Everyone’s going to pay attention,” he says. “It’s a little harder to come to an audience and be like, ‘Life is beautiful.’ People ignore you. It can be difficult to be optimistic in these days and times. But shouldn’t that be a storyteller’s job?”