Pop star Billie Eilish joined forces with famed filmmaker James Cameron to bring her "Hit Me Hard and Soft" tour to the big screen.

Released theatrically by Paramount Pictures on May 8, "Billie Eilish - Hit Me Hard and Soft: The Tour (Live in 3D)" is co-directed by the multi-Grammy winner, 24, and the "Avatar" and "Titanic" filmmaker, 71.

Shot mainly during the Manchester leg of the musician's 2024-25 world tour, the film combines Eilish's hit-packed performance with intimate and reflective moments off the stage.

Cameron reached out with an "idea ready to go", said Eilish, premiering the film in London on Tuesday, and getting to work with him was "a complete dream".

"This is my favourite show that I've ever created and favourite tour I've ever been on. And the fact that it's going to be captured forever, and it's also in 3D so everyone that didn't get to see it can live it... I'm just so grateful," she said.

Cameras, at times operated by Cameron, capture Eilish as she prepares to take the stage, warming up her voice, getting her ankles taped and applying her make-up. In calmer moments, buoyed by the director, she opens up about the origins and the motivations of her performance style and attire.

"It gets more into her heart and her mind and her kind of creative soul and into her relationship with the fans and what it means to them," said Cameron. "I find it quite heartfelt, in addition to the music and the show being great," he said.

The candid behind-the-scenes moments were Cameron's idea, Eilish said.

"I wasn't originally going to do that," she said. "He was like, 'People want to see it' and I'm now really, really glad that is part of the movie and I'm excited for people to see it."

The performance is brought to life with 17 cameras, said Cameron, many placed in the audience and catching raw emotions.

This is Eilish's second concert film and follows successful tour movies by superstars Taylor Swift and Beyonce, which topped the box office and gave a boost to cinemas.

"I think people like that communal experience. I think Billie's fans like to go together, it creates not only a bond with Billie, but a bond with each other," said Cameron. "They feel like it's a shared emotional experience. I'd be surprised if they don't sing back."

-Hanna Rantala/Reuters