ONE Sunday, aged 13, Katy Brand went to a church service on a family holiday and promptly became a fundamentalist Christian in a self-imposed conversion that would take hold for seven years.

So much so, she attended church four times a week, "putting the 'fun' into fundamentalism...and the 'mental'," she says, describing her teen self as an "obnoxious, self-important d**k, but at least I knew I was going to heaven".

Now Katy is not sure, as can be discovered in her comedy solo show I Was A Teenage Christian at Pocklington Arts Centre on Friday, where she will relive her glory days of certainty, judgement and unrequited love during her total immersion in evangelical Christianity, while trying to figure out what the hell was going on in her head.

Katy had subsequently converted to comedy in 2004, playing her first professional gig in a London pub, before joining the sketch comedy troupe Ealing Live!, and winning a British Comedy Award for her ITV2 sketch series Katy Brand’s Big Ass Show in 2008, since when she has worked as a journalist, screenwriter, actor, comedian, director and novelist, penning her debut work, Brenda Monk Is Funny, in 2014.

However, those evangelical days kept re-surfacing in her thoughts, to the point where she wrote I Was A Teenage Christian for her first solo show at the Edinburgh Fringe in ten years last summer.

"Predominantly I'd done sketch shows, but I had this idea for a show about my teenage conversion, doing it at Edinburgh pretty much as an experiment, learning how to do stand-up on the job, and I was definitely better by the end of the run," says the 38-year-old High Wycombe humorist, who has subsequently performed the show in London and now on tour.

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"Ironically, the thing that really killed it was doing a theology degree," says Katy

"I'd done solo sketches, but that feels much more like an acting job, putting on a performance, definitely not being yourself, but stand-up is a version of you where the audience gets a sense of you as a person and it has a feeling of being natural about it. I do feel very much myself on stage, which I'm enjoying, and that's surprised me."

This all adds to the honesty and frankness of I Was A Teenage Christian. "It all began when I was 13 and went on holiday with friends who'd joined a happy-clappy evangelical church and invited me to a service, and it was an almost an immediate response," Katy recalls. "I fell in love with the lead singer of this Christian rock band, so it was a pretty hormonal experience.

"It lasted seven years; I preached on street corners, in shopping centres and at schools, doing the Lord's work...and then I grew up."

What happened? "I started to have questions about it, thinking about their attitude to homosexuality, and the last straw was when they tried to ban Harry Potter books for promoting the occult," says Katy.

"Ironically, the thing that really killed it was doing a theology degree..though I did finish it. I'm not an atheist, I'm still interested in those questions, and I still quite like old churches, but I'm definitely not part of any formal religion."

Katy Brand in I Was A Teenage Christian, Pocklington Arts Centre, Friday, 8pm. Box office: pocklingtonartscentre.co.uk or 01759 301547.