Charli XCX felt vulnerable depicting the highs and lows of being a pop star in her new mockumentary 'The Moment'.

In her biggest acting role to date, the '360' hitmaker plays a fictionalised version of herself as a crew follows her for a tour documentary while she hits the road to support her smash hit album 'Brat'.

While she doesn't play her real self, and the circumstances are imagined, the British singer used the movie as an outlet to express some deeply personal opinions about the realities of pop stardom.

"It felt very vulnerable because I tapped into the most extreme parts of my personality that sometimes I feel the need to hide and diminish," Charli told The Hollywood Reporter.

Being an artist is a really volatile thing. One minute you can be on top of the world and think you are the best and the most important person in the room with the best ideas - a generational artist - and then the next minute you can feel like a piece of s**t on someone's shoe.

"I really feel that in my journey as an artist," she added. "To actualise that was hard because I don't like feeling, especially the latter version of that. It's scary to admit you feel like that."

Charli's close friend Aidan Zamiri, who co-wrote and directed the film from the singer's original idea, then recalled what she wrote in the initial document she sent to him.

"It was a piece of writing that captured the complexities of what it's like to achieve something that you've worked half your life for, but then to feel how fragile and how fleeting that might be," he shared.

Charli is able to be extremely honest in a way that most people would be frightened of - but I don't think it scares you.

The 'Von Dutch' hitmaker nodded in agreement and joked, "I just do it, then regret it all."

‘The Moment’, also starring Rosanna Arquette, Kate Berlant, Jamie Demetriou, and Kylie Jenner, is set to hit New Zealand cinemas on March 5.