Altman's latest mash-up

The veteran director is taking an unusual perspective on Garrison Keillor's legendary radio show.

For 30 years, Garrison Keillor has spent his Saturday nights putting on an old-fashioned radio show, A Prairie Home Companion, the live variety programme heard by four million. But while building an institution by raising Midwestern self-deprecation and subversively folksy tongue-in-cheek story-telling to an art form, he's been harbouring celluloid dreams - which is how his base at the Fitzgerald Theater was transformed last summer into the set of Robert Altman's latest film.

"This has been my ambition for years, to write for a dramatic medium," Keillor says. "Because I'm no good at it, and one aspires to do what one cannot do. I still have a hard time writing dialogue, because I come from people who didn't talk. We sat and chewed our food, looked out the window."

Keillor originally approached Altman with the idea of making a film based on the characters of Lake Wobegon, the mythical Minnesota town where much of his story-telling is based, after a deal at Disney fell apart. Altman decided that he'd rather make a film about the onstage drama and backstage dynamics surrounding the making of a radio show.

Keillor, 64, imagined a last night in the life of a programme much like his own, "turning the show inside out" by writing a scenario based on real and imagined Prairie Home Companion personalities. Writing a fictional documentary about himself was, Keillor says, "an odd assignment. But I was intrigued by the idea. And I was 60 years old. When you're 60, you kind of think to yourself, 'This chance may not come again'."

Regulars Sue Scott and Tim Russell play a make-up artist and stage manager respectively. The regular chanteuse Jearlyn Steele plays herself. Dusty and Lefty, the singing cowboys - character sketches incarnated on the radio by Keillor himself - are reborn in the hilarious duo of Woody Harrelson and John C Reilly. Prairie Home Companion icon Guy Noir is now the theatre's hapless security guard, played by Kevin Kline in 1940s attire. And central to the story are the country music sisters Yolanda and Rhonda Johnson (Meryl Streep and Lily Tomlin) and Yolanda's daughter, Lola (Lindsay Lohan).

"This is all in Keillor's mind," Altman says on a shooting break. "This has gotta be his humour, his tempo. I can't make up my own jokes. This is really about Garrison Keillor and his sense of humanity and his sensibility and his politics. All I'm doing is coming in and interpreting it. This guy's been in charge for 30 years. He has never, ever not been fully in charge of everything, except this movie. I have to see that he is in charge."

"No, he's the master of this world," Keillor insists later from a glass-encased VIP lounge at the back of the theatre that had been built by the art department for a scene in which Tommy Lee Jones - playing a broadcasting executive - comes to shut down the show. "Bob has an amazing, specific vision. He's painting his picture with some materials that I've provided. He has the upper hand. We know who makes the final cut."

"Keillor and Altman are a real natural combination," says Reilly, still in cowboy get-up. "There's something similar in the fabric of Prairie Home Companion and some of the more well-known Altman movies - where there's a group of people, one comes in, one comes out and there's humour in it that's based on the acceptance of humanity and all its flaws and eccentricities."

Keillor is known for rewriting right up until airtime, and much of the shoot involves Altman allowing him to hold forth from his stage, loomingly tall, in red tie and trainers, while the house band jams behind him and he and a rotating crew sing songs and jingles.

"Let's come in here now with a word about catchup," Keillor says in his homespun voice, delivering a service announcement for the fictional Catchup Advisory Board. "Yes, catchup - made from tomatoes that contain natural sunshine, which we need in this part of the country... We come from people who brought us up to believe that life is a struggle, and if you should ever feel really happy, be patient - this will pass." Then Altman yells, "cut!", from the back of the theatre. "That was great, Garrison," he says. "Let's try that one more time." Keillor improvises another take.

"I'm a writer, and there are times when I'm very proprietary about what I have written," Keillor says. "But there are scenes which I'm glad to see kind of smudged. Bob's very good at smudging. So the dialogue is kind of overlapping and a lot of things are going on. Had they been spoken like Shakespeare, everyone would have seen that it wasn't Shakespeare."

Keillor has spoofed himself in the bumbling alter ego of GK. "I am not playing myself exactly," he says, "I wanted somebody else to play me."

Who? "George Clooney, of course," he says. "I couldn't really give myself much to do in the screenplay, knowing what little I was capable of."

The local press has had its knickers in a bit of a twist about the celebrity onslaught, reporting Streep sightings in Marshall Field's and the restaurant habits of the cast. But not even the presence of the tabloid staple Lohan did much to disturb life in the quiet city of F Scott Fitzgerald's birth. Mickey's Diner at 7th and St Peter is always open, and the film-makers couldn't resist using the camera-ready 1930s greasy spoon as a location.

Keillor has finished shooting for the day and changed into jeans, which do little to lend him a casual air. For all the cosiness of his on-air persona, there is an awkwardness - his stature makes it hard for most people to look him in the eyes, and he seems never to slip out of character. The extras have gone home and Altman's chair has been moved on to the stage for a scene in the wings with Kline and Virginia Madsen (here as a dark angel in a trench coat). "In an early stage of development, Bob said, 'The death of an old man is not a tragedy,'" Keillor remembered. "I asked to write an angel into the script, and he gave it on the condition that there be no aura."

"Look at that - that's a picture," Keillor continues in a confidential hush, deflecting attention to the white-haired Altman, a pale, distant figure in the Caravaggio-esque house-light, surrounded by silhouettes of the crew. "He's in his own world up there. To the extent that I'm responsible for giving him something to work on that he's enthused about, I feel as if I've done a good deed in a dark world."

One night after shooting, Altman gathers a non-exclusive mob of cast, crew, family and friends for wine, beer, pizza and a glimpse of the work in progress. On screen, Harrelson and Reilly do a musical bad-joke routine, Streep and Tomlin sing sweetly, Kline becomes the flesh and blood of Guy Noir, and Keillor is both his oddly charming self and a suddenly probable leading man. Those assembled burst into spontaneous applause, and tears.