Cave no ordinary rock god

How do you make a documentary about Nick Cave, the dark prince of Australian rock, whose output since performing as The Birthday Party's fiery frontman has encompassed a catalogue of explosive, brooding and beautiful songs - songs of love and hate, murder and mayhem, lust and romantic longing - novels, film scores and screenplays?

For Jane Pollard and Iain Forysth, the British artists behind 20,000 Days on Earth - a ground-breaking new film about Cave and his artistry - the only option was to strive to create something as unique as the man himself.

"There was no point in making an 'all right' film about Nick Cave," Pollard tells me at the Berlin Film Festival. "Because Nick Cave's not all right. Nick Cave's f...ing extraordinary."

Cave batted away all previous advances from documentary- makers but had built up a relationship with the Goldsmith College alumni that made him comfortable enough to invite them into the studio at the inception of last year's gorgeous Nick Cave and the Bad Seeds album, Push the Sky Away.

"There's a tolerance and a trust that was important," Pollard explains. "We'd made a lot of work with Nick and he was the first musician to ask us to not make art but to make music videos (their first one was for the 2008 single Dig! Lazarus Dig!)."

They had had experiences where "you go in and everything's finished, and you find a sofa with a load of guys sat around going 'Can you turn the high-hat down,' and it's just really boring," Forsyth says.

Cave, though, was offering them something potentially much more exciting. "The idea that we could be there right at the beginning and see some of these little melodies starting to form, was just an incredible opportunity. So we jumped at it."

They took cameras in and started filming. While no one knew then exactly what kind of film would eventually emerge, the directors and Cave agreed that they didn't want to make The Nick Cave Story.

And they didn't want to do a traditional music documentary, with concert footage, talking heads and archive material. Meanwhile, they discovered they shared a fondness for the outrageous but sincere Led Zeppelin film, The Song Remains the Same.

During a Q&A in Berlin, Cave noted that although it was "embarrassing" in places, the Zeppelin film "comes from a period where rock singers, not only were they viewed as gods but they viewed themselves as gods".

"There was an aspiration of this band in this documentary that they were something immortal, something larger than life. And that period, which I grew up through, my great heroes, such as David Bowie and Bryan Ferry, were very much characters that lived in the stratosphere."

He lamented the "democratisation" of the music world, claiming that it had pulled these people down. "And now we have a kind of level playing ground of mediocrity."

Forsyth picks up the theme the next day, suggesting that music documentaries often "want to normalise the subject and make a big statement about how the rock star is also a normal person". He claims that it would've been disingenuous to do this to Cave.

"I've spent a lot of time with Nick and he is not a normal person. His life isn't a normal life. So we wanted to avoid all that 'Nick taking the kids to school' or 'Nick doing the washing up' stuff."

They tried to get inside his head and his heart. And instead of tearing down the mythology that has accrued around Cave, they added to it. The film isn't backward-looking but takes place in the present tense, over one imaginary day. And a busy one, at that.

In one revealing scene, Cave visits a psychoanalyst (something he has never done in real life) and talks candidly about his childhood and the death of his father, Colin, in a car accident, when he was 19. While the office they're sitting in is a set, the Freudian shrink was real.

The strategy of sitting Cave down with a psychoanalyst produced an "embarrassment of riches", Pollard says. "We were then able to really hone in on the topics that we thought were the strongest, and the themes that were able to play through."

Cave's second novel, The Death of Bunny Munro, inspired another ploy to get him to open up. This time the filmmakers put Cave in a Jag with, separately, Ray Winstone, former Bad Seed Blixa (Bargeld), and Kylie Minogue, and filmed as they talked.

For the filmmakers, the three interlocutors are "figments of Nick's imagination . . . (in the shape of identifiable people) that have had an impact on his life, or their paths have crossed in some way".

Winstone discusses ageing and the difference between actors and singers ("Actors get the privilege of putting on and taking off masks," Forsyth says, "whereas musicians - the good ones, like Nick - become the thing that they created"); Minogue brings out Cave's tender side; and Bargeld's participation allows the estranged ex-bandmates to finally wrap up some "unfinished business" concerning the German's sudden departure from the Bad Seeds.

By daring to take chances they have created an insightful and exhilarating portrait of a man who, at 56, still burns with passion and creative energy.

"The awe that people have around Nick is not just about how great he looks and the persona and the performer, it's also about how hard he works," Pollard says. "So the feeling we want to leave you with is 'God, I just should do it. I should just get on.' Whatever it is, just get on and stop wasting time."

'There was no point in making an "all right" film about Nick Cave, because (he's) not all right. Nick Cave's f...ing extraordinary.'

20,000 Days on Earth opens tomorrow.