A NEW film about Leonard Cohen does a remarkable thing: it gets him to talk. And what a pleasure it is. Here's Cohen, for example, on his longstanding reputation as a ladies' man - it was, he says, "a joke. It caused me to laugh bitterly the 10,000 nights I spent alone."

Such humour is unexpected and bracing. And it is part and parcel of the audacious blend of concert footage and talking-head interview that makes up Leonard Cohen: I'm Your Man.

The film, directed by Lian Lunson, an Australian producer and former actress, attempts the equivalent of scooping up mercury with bare hands: pinning down the elusive Cohen through his personal reminiscences and performances of his songs by admirers.

It has already been warmly received at the Sundance and Berlin festivals this year. Britain saw it at the Cambridge Film Festival this month and Australian audiences are expected to see it later this year, although the release date is undecided.

It all started with a concert at the Sydney Opera House in January last year to mark Canadian-born Cohen's 70th birthday. Artists including Nick Cave, Rufus Wainwright, Jarvis Cocker, Antony of the Johnsons and Beth Orton showed up to perform Cohen songs. Lunson filmed them, taking the gamble that if Cohen would talk about himself on camera, the blend of confessional and concert footage would make an arresting documentary.

Her hunch was largely correct, although inevitably the quality of the cover versions varies from performer to performer. Wainwright pops up most often, offering Chelsea Hotel No. 2 (Cohen's wry memoir of a sexual encounter with Janis Joplin), a jaunty Everybody Knows and the ubiquitous Cohen anthem Hallelujah.

Cave does Suzanne and I'm Your Man with respect. But Antony is a revelation, his tremulous falsetto elevating If It Be Your Will to new heights even if the deadpan wit of Death of a Ladies' Man seems to elude Cocker and Orton.

The really bad news coincides with the arrival of half of U2 on screen. Bono and the Edge (who did not take part in the Sydney concert) pay squirm-inducing verbal tributes; Edge compares Cohen to Moses, "coming down from the mountaintop with tablets of stone". That must have given the old boy a grim chuckle.

The Irishmen partly redeem themselves by accompanying Cohen in the film's final scenes, when his world-weary bass-baritone singing voice is finally heard on Tower of Song, in a performance produced for the film.

"I felt all these songs were like chapters in his life, and that somehow all these different performers were all different parts of him," Lunson says. "I wanted the film to really show the essence of Leonard Cohen."

Whether or not she succeeded, the appeal of her film will vary for different generations. Younger audiences unfamiliar with Cohen will be intrigued that this quietly spoken, gentle-mannered septuagenarian could wield such huge influence on the work of Cave and Wainwright, among others.

Here he is on camera, talking candidly about his life and work: stumbling on poetry in the Jewish liturgy at his local Montreal synagogue; his prickly relationship with the literary scene in his native city; being ordained as a Buddhist monk after studying with a Japanese Zen master in California in the 1990s.

The treat is that he has been largely out of the public gaze for the past 12 years, and yet here he is being interviewed, revealing a dark and subtly buried humour, and choosing his words as carefully in conversation as in his finely wrought lyrics.

Cohen shows a beguiling humility about his contribution to music and letters.

"I had the title 'poet', and maybe for a while I was one," he reflects. "Also the title 'singer' was kindly accorded me - even though I could barely carry a tune."

In the same vein, he speaks about learning to embrace failure and disappointment.

Even on the trainspotterish level of illuminating lyrics, Cohen has something to offer. If you wanted to know what lay behind that line about "tea and oranges" in Suzanne, this is the film for you.

Lunson's end result isn't perfect, but it provides a valuable document about an artist too rarely glimpsed. And if new audiences scurry out to sample Cohen's work in its original form, so much the better.

Telegraph, London