Twenty-one years after Nirvana frontman Kurt Cobain took his life in April 1994, the first authorised documentary about the rock hero is being released. Kurt Cobain: Montage of Heck, by Oscar-nominated film-maker Brett Morgen, was made with Cobain's daughter, Frances Bean Cobain, acting as executive producer.
According to Morgen, the project started eight years ago in 2007, when the singer's widow, Courtney Love, approached him about making a film.
"She liked what I'd done with a documentary I'd made called The Kid Stays in the Picture, about Hollywood producer Robert Evans. She asked if I'd be interested in doing something on Kurt. When I said yes, she brought me crates and boxes containing all of Kurt's stuff and just told me to go ahead, there were no restrictions placed on me whatsoever. She didn't see anything until I showed her my edit."
That archive contained around 4,000 pages of the singer's journals, as well as home videos, audio tracks, and also audio diaries Cobain recorded from a young age.
Morgen says his intention is "to introduce you to Kurt Cobain for the very first time - the man, not the legend."
Cobain's body was found at his Seattle home on April 8, 1994. A post mortem concluded he'd committed suicide three days earlier. He was 27-years old and, as Morgen puts it, "the global icon of the time, Nirvana had produced a Camelot for grunge music, and Kurt was its King."
The years have not diminished Nirvana's appeal - by 2014, the band had sold 75 million albums around the world, and Morgen accepts that fans will scrutinise the documentary, named after a mixtape the young singer made in 1988.
"As a fan, there is something cathartic watching the movie - it's like meeting a friend and we get to be with him, " he says. "It's a very joyful film as it's a celebration of Kurt's creativity but the pathos comes when you realise the film's over and that's it. You were just getting to know him, and there's no more, and there will never be any more.
"But it's a funny film, you know - people didn't realise how very funny Kurt Cobain was, or how romantic he was, or what a doting father he was. Ultimately the mythology of the man is that he was in pursuit of fame, and then he didn't want fame anymore. I hope this film shatters that illusion. I think Kurt, the child of a divorce, was in pursuit of family his whole life, and when that became defiled that's what ultimately led him to take his own life.
"But I didn't make this film for fans. I made it for Frances."
According to Morgen, Frances Bean, 22, introduced herself to him saying: "Hello, I'm Frances, and I know you better than I know my father."
He continues, "She hasn't been given a good hand. It's got to be completely bizarre for your father to have left you when you were two years old and for people to be coming up to you daily and saying, 'oh, your dad was so amazing.'
"I think she's been wary of getting to know him, so she hadn't seen any of the material in this film, and when I showed her the first edit, I think it lifted a huge burden from her. Most kids blame themselves when their parents leave in one way or another, and it's clear from this film that Kurt Cobain's problems pre-dated her and Courtney, and pre-dated Nirvana.
"There is one very-hard-to-watch scene where Kurt is giving Frances her first hair cut, and he is totally out of it. You can see the battle that is going on with him to stay with her, but it was a battle he was losing. But it's obvious to see how very much he loved her. So I think for Frances she was liberated in knowing that her dad loved her and that his suicide was nothing to do with her.
"At the end of the film, she turned to me and said, 'thank you, you've given me two hours with my dad that I've never had'. She never asked for a single change to be made.
"Similarly for Courtney, it means a lot. She watched it with me, and then she watched it at two premieres. I said to her, 'do you really want to see this again?' And she replied, 'Yes, it's as close as I've got to Kurt in 20 years, and this way I get to spend time with him again.' I can speak for both of them when I say how thrilled we all are to be showing this to the world."
There was never an intention, according to Morgen, for Courtney Love to serve as producer as well as her daughter.
It was Frances Bean, he says, who introduced him to Kurt's family, who all give interviews for the first time in the film. Nirvana bassist Krist Novoselic also contributes, as does Courtney Love, while an interview with drummer Dave Grohl was too late to make the edit for the world premiere at the Sundance Film Festival in Utah, where the documentary gained rave reviews.
Rolling Stone magazine says that it "stuns … by the time you get to the final shot .. you don't just feel that you've gotten to know the man better, you're left completely emotionally spent."
Morgen was Oscar-nominated for boxing film On the Ropes in 1999, and also made Crossfire Hurricane, about the Rolling Stones.
"This is by far the biggest project I've ever worked on. Kurt had a major impact on my generation and we're almost the same age - I'm 46 now," he says.
"I never knew him in life, but because I read all his journals and saw his art, and he was so expressive and personal, that I felt he was my friend - I really, really liked him.
"Finishing this movie was one of the saddest days of my life as a film-maker, because I knew I couldn't be with him anymore. I spent eight years with Kurt Cobain and I felt I got closer to him than anyone outside my own family."
Kurt Cobain: Montage of Heck is released in the UK on 10 April.