It takes either extreme foolishness or bravery to bare your soul in public.

Arts journalist Jasper Rees though has done precisely that. A few years ago, confronting a mid-life crisis and stumbling upon a cure via the resurrection of a long lost relationship with the French horn he played as a schoolboy, he produced an autobiography, I Found My Horn.

Cue one Jonathan Guy Lewis, actor, writer, director – a promising schoolboy horn player who, like Rees, turned his back on it. The result, a homage to the horn (and maybe in parenthesis the Flanders & Swan song that Introduces it) gave Lewis an opportunity to perform a prodigious feat of acting and a gallery of characters from `Jasper’, to his eccentric music teacher, `Cartlidge’ and on into `Dave’ Lee, the colourful northern horn player who inspires him to continue his quest to play the solo at the annual British Horn Society concert.

Launched originally in 2008/9 at Chichester, Hampstead and elsewhere, this present incarnation now sees an added fictional and bolshie son, Daniel, and even more alarmingly, the Czech voice of the horn. He wants a say in here, too.

The result is a remarkably affecting, not to say life-enhancing blast. When life seems meaningless and hopeless the answer can be to change tack and set oneself an impossible goal. The achievement, no matter how less than perfect, will be its own reward.

This truism is delightfully portrayed by Lewis and `Jasper’ in a tone that laced with a light veneer of self deprecating irony also covers passion, humiliation, frustration, comic observation and much else besides. I Found My Horn, is, after all, the story of an obsession.

It’s a fantastic tour de force by Lewis. And despite one or two surprising production longueurs, by the time we reach `Jasper’’s concert solo and the playing of the Rondo from Mozart’s Horn Concerto no 3, at first haltingly then moving to a triumphant climax, every single audience member, I’d guarantee, are right in there with him, willing him – and themselves – on.

We all have to overcome our demons. I Found My Horn gleefully shows how it can be done, no matter how apparently absurd the choice.