Angel wings and vampire fangs

He started his career at the Bar and then became a civil servant, but he "always felt like that wasn't the important bit - I've always been creative and have painted, written and performed."

You can't buy nice angel wings in a joke shop

It was this search for his true identity and for a career that he found fulfilling, that inspired the character of the eponymous angel in Osner's Edinburgh play.

The character is a retelling of the archangel Gabriel "who gets fed up with being God's messenger and going around announcing things; he just wants to play his trumpet. So he goes down to New Orleans and plays his trumpet. He's a slightly fallen angel but very much on his own terms." Which sums up Osner's pursuit of happiness since retiring from the civil service and "changing my way of life completely" in 2008, writing, producing and performing in a number of feature films and plays.

"I've used aspects of my life," he explains, "because I think people like to hear a story."

The civil service aside (civil servants don't have the most creative of reputations, although it was actually at the Ministry of Justice that Osner discovered his talent for writing and producing: "We put on Christmas shows, which I wrote. That's when I started performing") Osner's career choices always hinted at his creative character.

"I chose the Bar more for the look of it than the law stuff," he says, talking about getting dressed up in a gown and wig and the expositions he'd have to do in front of the court.

"Lots of the law is boring - you don't get all the drama you see on TV - but I did enjoy addressing the jury."

However, he left the legal profession in his twenties to enter the public sector and reflects that his years in "normal" jobs have helped him get where he is today. "It's probably made me more exact," he says. "As a civil servant you get trained to write and draft and the exact meaning of words."

It could have been so different. He turned down an invitation in his youth to work for a repertory company. "I'm afraid in those days I was too frightened to go off and do it, so I lost that opportunity." Nevertheless, ever the optimist, he doesn't regret the path he chose. "I'm now financially set up so I can go off and do [my own show and perform at Edinburgh]. We don't know how it would have been if I'd started in my early twenties."

While it might be clear how Osner's professional life has influenced his creative endeavours, his personal life remains a bit more of a mystery, but one that he does not shy away from exposing.

The show opens with an "angry goth" singing Don't Label Me, "because I think people label other people too much". Another song in the show, Spare Man Blues, explores a younger Osner's inability to get a girlfriend, "but women were always happy to go out with me as friends." Although he concludes that this isn't something that preoccupies him too much any more.

His Judaism isn't something he refers to directly but he says that there is a current of it running throughout his work. "[The show] has a bitter-sweet tinge," he says, sounding wistful and somewhat bitter-sweet himself. "That's pretty Jewish isn't it?!"

A "confirmed Liberal Jew at 16", his original angel was in fact Jewish, "but there was something wrong with it; it didn't seem to quite gel, so I re-wrote it as a rhyming monologue." And he became Irish in the process ("because I like doing accents"), drawing on a different immigrant experience from that of Osner's grandparents, three of whom "came over from Eastern Europe".

Unfortunately, however, it seems that the audiences of London – where Osner has so far previewed his show - didn't warm to his Jewish angel, whereas reception of the Irish trumpet player has been more successful. "You have to go with it if people aren't liking it. I think the first angel was too angry, whereas this one is more charming, enjoying telling his own story."

For Osner that is the beauty of a medium like cabaret; different roles, different performances, songs, spoken word, even dance - the world is Osner's oyster.

Although he is a bit of a purist. "Cabaret means so many different things now. It can mean burlesque - which it isn't," he laments, "or singing the standard American songbook - but other people can do that better than me. I'm more interested in being myself."

And, in doing so, he really is laying his whole self on the line. "I want people to like what I'm doing," he says, "that's why I'm going to Edinburgh. People in Edinburgh are up for seeing shows and taking risks if something looks interesting."

But taking part in the festival is not the easy option. Osner is performing 20 shows in total and "there is such a lot to do - the show itself, which in some respects is the easiest bit; then the costumes (Osner had his angel wings handmade because "you can't buy nice wings in the joke shop"); finding somewhere to stay; then you've got to get people interested."

This may be the hardest part. Osner says he has sent out around 100 press releases so far and has rented a microphone and speaker so he can stand in the square and preview his act, tempting people to see the full show, as well as talking to people and handing out flyers. With more than 3,000 shows for punters to see throughout the festival, Osner has to make his mark.

He started planning his visit over a year ago and booked his venue ("a very nice space") in January. "Basically, I've been on this since last year and have really been going at it non-stop." His advice to any would-be festival performers? "Work out when you need to start and start six weeks earlier!"

Hard as it has been and will be, Osner doesn't have second thoughts. "There's such a wonderful atmosphere [at Edinburgh] and I wanted to push myself forward," he says. "So, I thought to myself, I have to go. It's quite exciting, quite intimidating as well. I'm looking forward to doing it and getting into a role."

Angel to Vampire, Space Triplex (venue 38) 5-27 August.