Hearing AL Kennedy is doing stand-up at the Edinburgh festival is a little like hearing Morrissey has been cast in Singin’ in the Rain. Both have a swollen streak of bleak humour running through the dark heart of their creativity, but somehow you can’t imagine them pausing for applause before ripping into the next cheerful belter. And yet it’s true. (The AL Kennedy bit, not the Morrissey bit. For that, we can only dream.) The Fringe programme describes her show, Feel the Love, thus: “Novelist on the run explains the hazards of the writing life. Pot Noodle, sharks, internal examinations, Blair, semicolons, backache, perversion, Microsoft, paranoia, decomposition. Like watching a midlife crisis, but without the carefree sex and red cars.”

“Yeah, I know,” she shrugs, when asked to explain the paragraph, “but everybody has to write the stuff for the programme ages before they have a show.” Her stand-up, she says, evolved from her role as a sort of light-relief speaker at political meetings over the past five years. She took to it in earnest 18 months ago, after the end of an intense friendship — the absence of which left her feeling so grim, she saw her sanity and cheerfulness hanging by a thread. “If I hadn’t turned to comedy, I would have hanged myself,” she says, so deadpan that it’s hard to tell if she is joking. She will not speak about the relationship, but she thinks the comedy has helped.

“Although you can’t replace missing funny by writing funny yourself, it takes all the concentration that you have, and so it’s very distracting,” she says thoughtfully. “And it develops its own momentum. Material spawns other material, and I think that appeals to obsessive-compulsives. I mean, if I’m having fun, I twitch. How obsessive is that? I twitch if a gig’s going well. So I’m a sort of circus freak — I like to twitch in front of a room full of strangers.”

Twitching aside, Kennedy’s Edinburgh show contains material built up over the past 18 months, with a sizeable chunk of new stuff. “There are elements of daftness, elements of politics, a bit where I whinge about my other job and a lot of stuff where I whinge about being me — which seems to go down well, even with people I’ve previously alienated,” she says. “It’s quite dark, and I have to keep remembering to be in some way welcoming, but the gift that I bring is in realising that you don’t have to be me. You will definitely get that — ‘Thank God I’m not her.’”

Although she professes to hate gag-telling comics, preferring the more personal routines of Dave Allen and Richard Pryor — “The comedians who work for me are the ones that make me forget I’m going to die” — she has some smart punch lines and even a decent knob gag. When she tells me the knob gag, I laugh (because it’s funny). She, however, groans. “People always laugh at that,” she complains. “It’s so cheap, I actually object to it. You feel dirty after telling a joke like that.”

Even so, it is perfectly timed. And, despite the aforementioned bleak humour, it is still strange to hear the author of Now That You’re Back (“angry, tender and despairing” — Elle) and Looking for the Possible Dance (“complex, layered narrative and ... a shocking climax that is ... not a bit gratuitous” — Salman Rushdie) telling a knob gag.

Perhaps it is that very contrast between the intensity of her novels and the jovial tomfoolery of stand-up, or perhaps it is a secret wish for a pratfall, that has the media flocking around her foray into funny. A BBC2 crew is making a documentary about her stint on the Fringe, while another BBC2 crew films that crew. She has thus performed three recent gigs under the heat of two sets of TV lights. “There is a temperature above which comedy audiences physically can’t laugh — they just get surly and tearful, and the front row’s faces melt,” she says with an air of cheerful fatalism.

“All the other comics hate me for the free publicity I’m getting, so I’m up there thinking, ‘What the hell am I doing here? This is almost as bad as my real life. Somebody tell me that they love me and betray me horribly in the next 20 minutes, please. That will make everything fine, and I’ll know where I am.’”

Kennedy acknowledges the benefits of such interest — if only in terms of drumming up an audience. That, she points out, is why I’m interviewing her rather than one of the 8,000 other people on the Fringe. Her world-view being as it is, however, she fears the attention may prove toxic.

“I don’t know who will actually turn up to see me,” she says. “I do have a horror of thinking that it’ll be one-third journalists who want to murder me for stepping out of the box, one-third novelists who hate me and one-third comics who want to stare at me because I’m clearly mad. And two little old ladies at the front, who don’t expect a novelist to be talking about masturbating cats. So, yes, since you ask, I’m quite looking forward to it.”

Plot shots: comedians catch the writing bug

Although Charles Dickens spent his final years performing stories in a solo show, and Truman Capote liked to showcase work-in-progress live, AL Kennedy’s move into stand-up is unusual for an author. But for comedians, the desire to write a novel seems to start with their first 10-minute spot. Many go for feelgood — Dominic Holland’s The Ripple Effect; others add existential angst — Sean Hughes’s It’s What He Would’ve Wanted. Some grow more ambitious over time — Ben Elton’s recent novel The First Casualty deals with shell shock and murder — while others start there: David Baddiel went for psychosis and cultural identity in his debut, Time for Bed. Native Americans often appear, as in Stewart Lee’s The Perfect Fool and Robert Newman’s The Fountain at the Centre of the World. Comedians-turned-novelists can find it hard to come up with a sustainable plot. Stephen Fry overcame that by taking inspiration from The Count of Monte Cristo for The Stars’ Tennis Balls.

Feel the Love is at The Stand 2 at 3pm, Aug 5-27