Helen Reddy had always been very clear on how the lyrics of her most famous song came to her, lying in bed when the words, “I am strong, I am invincible, I am woman” began to run through her mind, and when she told this to Unjoo Moon, the filmmaker got an idea.

“We needed to find a more emotional and cinematic way of showing where she was at at that moment of her life,” says Moon, who once switched placards at an awards dinner to sit closer to the singer, having held her in awe while growing up in Australia. “I knew those words always came to Helen because of where she was in her life at that moment, because of the frustration she felt as an artist trying to find the right song to sing and being sent the lyrics to songs where she felt, “Why would you want to say those words as a woman?” But also she was very impacted by what was happening with the women’s movement and of being a mother to a daughter.”

You can see from the way the light touches the forehead of Reddy, as played by Tilda Cobham-Hervey in “I Am Woman,” that inspiration has struck, but Moon makes sure that glow allows room for her daughter as well as she’s tucking her into bed, recasting a biopic of the popular entertainer as a call to arms for younger generations to build upon the work she did navigating the misogynistic leanings of the music industry to create a rousing anthem for women globally. Spanning three decades of her career from when she arrives in New York in 1966 from Melbourne, playing small jazz lounges, to being taken under the wing of manager and future husband Jeff Wald (Evan Peters) to live the fast life in Los Angeles, the film chronicles how someone who could sing so confidently about female power largely lacked it in her own life, unable to make decisions about her future when her husband controlled the finances and record companies dictated what kind of music she would perform.

With fellow ex-pat and rock journalist Lilian Roxon (a feisty Danielle MacDonald) around to sympathize, Reddy takes what is within her control, namely her tremendous voice, and makes the most of it, much like the film’s director, who creates an epic retelling of the artist’s history when such stories are typically told on a smaller scale. With the film arriving in virtual cinemas (and even a few physical ones) around the world this week after a celebrated festival run that began this time last year in Toronto, Moon spoke about taking the plunge into narrative filmmaking after last profiling an iconic singer with the Tony Bennett documentary “The Zen of Bennett,” knowing when she had the right actress to play Reddy and how she incorporated a passing of the torch into the film.

You’ve made documentaries about musicians before, and I understand that was under consideration here. What made you want to pursue this as a narrative feature?

It’s really because as I started to get to know Helen better, I realized the impact and the scope and the depth and breadth of her career. I was quite young when Helen Reddy’s music was on the radio, so my memory of those years are really about the way her music used to impact my mother and her friends. But as I got to know Helen better, I realized she had this incredible personal journey that really had the scope to create a cinematic story and that we could probably be more effective in telling the world her story in this way. I had to really convince Helen to make it a movie, [which is] a very hard thing for someone to give their film rights away to another person, especially when you don’t know what they’re going to do. But at that time, Helen’s son was her manager and Jordan also believed with me that it should be a movie, so really the two of us encouraged Helen to consider it, and she came to really trust me.

I spent a lot of time talking with her. We’d go for walks on the beach, we’d go for lunch in Santa Monica and when we decided we were going to do a movie, I said to her, “Helen, okay, we’re not going to make a documentary so I’m not going to get everything right in your life. I’m not going to recollect every word and conversation that you had. I’m not going to fit everybody that’s been in your life into this movie and I might miss out some very key people who are a big part of your life, but I promise you that in the film I make, I will absolutely honor the spirit of who you are, what your life is and the impact that you’ve had on people and the impact your music has had.” I think that really gave her the confidence to move forward.

When your own initial consciousness of her is as an icon, was there something that came as a surprise as you got to know her as a person that you wanted to come across in the film?

I’ve gotten to know her so well nothing is really surprising, but the big thing was what it was like for her to arrive in America with a young child and those years where “I Am Woman” hits number one, she’s pregnant most of the time and then she has a very young baby. People don’t remember that aspect of Helen. They just remember that she was on all those television shows, she was touring, she was one of the highest paid entertainers in the world at that time, but she was essentially a working mother and she had a very young son and a daughter. That’s something I really tried to build into the movie because it’s not something you always see and it’s something I hadn’t really thought of until I got to know her better and see how important those relationships with her children are, which is evidenced in the way her daughter encourages her to go and sing at the end of the movie.

What sold you on Tilda to play Helen?

Now, I can’t ever imagine anybody else playing Helen. That was the hardest role in the movie to cast because a lot of people know who Helen is, so they’re going to remember and compare her and if you don’t know who Helen is, you’re going to watch the movie and get straight onto the web and you’re going to look her up. There’s so many incredible videos of Helen Reddy hosting “The Midnight Special,” “The Helen Reddy Show,” and “The Carol Burnett Show,” so we really needed to find somebody who could totally embrace this character and melt into this role. We had been searching for about a year and we had lots of different casting directors looking in five countries and Tilda wasn’t even on a casting list. I just saw a photo of her. She was standing in the street and she just had a stance that reminded me of Helen. Then when I researched her, I saw an incredible movie she made called “52 Tuesdays,” which really showed her scope as an actor rather than anything she would do in the creation of Helen.

When I met her, I could tell pretty quickly in the first 15 minutes that she has lived an unconventional life. Her mother was a ballet dancer and her dad was in theater, and Helen had grown up in a vaudeville family and traveled and Tilda had done something similar, so she was wiser and older than her years. She was only 22 when I first met her and she’s 25 now, and Helen in the movie ages from 25 to 48, so that’s a big task for her to undertake. I just knew that when you meet Tilda, she would be able to bring her dedication and her spirit to embrace this role. And then of course, she worked incredibly hard and we were able to support her in so many ways. She learned to sing. She had voice classes to try and speak like Helen. She had movement lessons. She did choreography. She had a chin piece, false teeth,and different body suits on and of course, the most incredible cinematographer Dion Beebe, who I also happened to be married to, he really helped in the creation with hair and makeup. I think it worked really beautifully because the real Jeff Wald when he saw the film, he said to me at times he thought he was watching Helen.

I’m glad you brought up the YouTube clips because I think this could pass for any of shows she was on. What was it like to recreate this many locations from the period?

You can see what a challenge that was because we recreated Los Angeles, Washington and New York in the ‘60s, ‘70s and ‘80s all on the streets and suburbs of Sydney, Australia and we only has six weeks to shoot the movie. I couldn’t recreate the Capitol Records building, so we went and did some key outdoor sequences in Los Angeles, but recreating that within the tight schedule and budget that we had was super challenging. We were able to do it because we knew very much those locations firsthand. Dion and I have lived in Los Angeles for a very long time and we both lived and worked in New York, so we knew those streets and we went to visit every house that Helen had lived in in Los Angeles – everything that’s recreated in Sydney, Dion and I scouted in Los Angeles and even in New York, we visited the original Hotel Albert. Then we had a wonderful production designer who lives in Australia [now], but had lived in America and his background is in architecture, so the detailing of what we were looking for, he was very specific with.

Then with Washington, I was there in 2017 during the Women’s March and I stood in the exact same spot Helen was in when she sings “I Am Woman” in 1989 at the end of the movie. I stood at the Lincoln Memorial and looked at the sea of pink hats, so I really got a firsthand feel of what that end scene would be. Then of course, we worked with an amazing visual effects house who helped us create that, but even though we were recreating that, we [had been] there in the actual locations.

After seeing the film, I was touched to learn that it was actually Helen’s granddaughter Lily Donat who sings the end credits song “Revolution” in the film. What went into bringing her into the fold?

I’m so glad you asked that because we just opened in Australia and can you believe I actually got to go to the cinema where there were four cinema screenings with actual audiences? It was extraordinary to be back in the cinema, and currently the film’s trending number one in Australia at the moment, which is super-exciting, but I love that it’s also the first time in history that both a grandmother and a granddaughter have hit the top 40 in Australia. Helen is [back] right now with “I Am Woman” and Lily is in the top 40 in Australia with our original song “Revolution.”

“Revolution” was written by this amazing Australian writer/producer Alex Hope, who just recently did the new Alanis Morrisette album and she’s a tour de force in herself, and what’s really wonderful is we always saw the song as continuing the legacy of “I Am Woman.” “I Am Woman” talks about “I Am Strong, I Am Invincible, I Am Woman” and “Revolution” is the song that talks about “We Are Mothers, We Are Daughters, We Are Sisters, We Are Friends” and he refrain of the song is “Here comes the revolution. Voices clear, voices loud” and as you can see after you watch the film, it’s about the continuation of the fight for women and I hope that women are still inspired to fight further and push boundaries.

We knew that Lily was a singer and we were just looking to incorporate her into the movie in some way, and we pull that story of Helen and her daughter through the movie, and we listened to a couple of submissions of original songs and when this song [“Revolution”] came, I remember so clearly, I was shooting in Pip Street in Australia, trying to make that look like New York and it was a horrible day because the fires were going on in Los Angeles, so I kept getting texts every 10 minutes, saying, “Oh yes, I think your house might be burning down.” [laughs] The whole time it was crazy. But the song came in and our producer Rosemary Blight said, “Listen to this.” I listened to it and we both knew it was the song for our movie, and the fact we were able to get Lili to sing the song is just really beautiful. It’s all part of the continuation of generations, which is what this movie is about in some ways.

“I Am Woman” opens in virtual cinemas and on demand on September 11th.