Back in 1965, when the notion of an indigenous Irish film industry seemed like a flight of pure fantasy, a bunch of brave souls set out to make the first truly Irish musical, a bawdy, boisterous comedy with overtones of The Threepenny Opera, based on some of the country's favourite ballads, and featuring some of its best-known performers.

Abandoned, unfinished and forgotten, for three decades, the film finally receives its premiere at this year's festival, in a special screening which will be attended by many of those involved in its making.

Taking as its starting point the song The Night Before Larry Got Stretched, O'Donoghue's Opera, (Saturday March 7th, IFC, 6.30 p.m.) stars Ronnie Drew as "the cleverest burglar in all Ireland" and appearances by Seamus Ennis, The Dubliners, the McKenna Folk Group and the Grehan Sisters. The beautiful 35 millimetre black-and-white footage of music sessions in O'Donoghue's pub on Merrion Row shows Dublin bohemian life at the start of the folk music boom - duffel-coated beat kids mingling with crinkly traditional types over innumerable pints of stout (drink features strongly in almost every shot in the film). It's a fascinating glimpse of a world which now seems very far away.

O'Donoghue's Opera was directed and produced by the late Kevin Sheldon, a director with RTE. Abandoned due to lack of finance and never completed, the film disappeared for more than 30 years, until the cutting copy showed up last year. Tom Hayes, who had acted as line producer on the original production, showed it to film editor Se Merry Doyle and to Tony McMahon in RTE. Doyle set about reconstructing the film from the existing footage. "I tried to find any information I could about it but it was impossible to find the original negative, so I had to work from the cutting copy and out-takes," says Doyle. "I'm hoping when it comes out that somebody might show up with the original."