Eva arrives 10 minutes into the show, interrupting comedian Josie Long in full flow.

"The audience has doubled in size," Josie hurrahs. "I'm no' that big," Eva replies as she settles down on the nearest comfy seat.

In fact Josie's maths is actually slightly askew. There are nine of us squeezed into the front room of Janet Sharkie's retirement flat on the edge of Leith. I think that qualifies as a full house (so much so that Steve the photographer has to wait outside). Those nine include Janet, her friends, her helpers, some bloke from The Herald, the show's producer, Angie, and the performers. Who are? Well, the aforementioned Josie Long, who you may already know from Radio 4 appearances, Edinburgh Fringe shows and/or her Guardian cartoon. And Dolly Parton,

Okay, it's not really Dolly Parton. It's actually Grace Petrie, singer-songwriter and for one day only Parton impersonator. Because Janet really likes Dolly Parton, so it seemed only fair to give her a couple of Dolly songs. What was your knowledge of Dolly Parton, before this, Grace? "- Before 1am this morning? Sketchy. I respect her as a songwriter but she wouldn't be my go-to cover of choice."

You wouldn't know it. As Grace essays a pretty decent version of Jolene, Josie is "offstage". Which translates as crouching behind Janet's telly. When Dolly leaves the building Josie stands up to tell jokes about Tamagotchis, tell us her boyfriend is a "Scottish man" and that she once climbed to the top of Mount Kenya. Which is in Kenya, you won't be surprised to hear.

All of this is done in a sweetly amusing way. And while wearing a Sleater-Kinney T-shirt. Josie – we're jammed up so close it would seem strange to be more formal – navigates the strangeness of the situation with aplomb. Even the moment when Eva's phone goes off in the middle of the show. You could say she looks very at home. "If just one person laughs that counts as 500 people laughing," she tells us at the start of the show. "If no-one's laughing that's still 100 people laughing."

Some 4500 laughs (at least) later Josie, Grace and I are sitting in Valvona & Crolla a short walk away talking over a post-show coffee.

"It's really tricky performing to people who are 70 and 80," Josie admits. "That's so outside my comfort zone. So to get any laughs out of them made me very, very proud." She's proud, too, to have got through the show without swearing, she adds. "Normally I love swearing."

Janet's front-room gig was the fourth of five front-room gigs for Josie and Grace this week. It's part of six weeks of special events that will see the likes of Karine Polwart, Tam Dean Burn and Wounded Knee's Drew Wright turning up in someone's home to perform. The someones are all people who for various reasons are unable to get to the theatre very much. Already this week Josie and Grace have performed to a man with MS who had limited movement and speech (Josie made him a heckleboard but he was too polite to use it) and a blind disabled man for whom she did some spoof audio descriptions ("Josie has just done two back flips in a row -").

It's all at the instigation of arts organisation Trigger, a project simply titled Visit, which likes to take artists and place them in challenging and different situations. For this project Trigger is working in partnership with organisations such as the Glasgow Housing Association, Alzheimer Scotland, Enable Scotland, Neighbourhood Networks, Receive MS Support and Ecas Edinburgh to take art and artists into new areas.

"What I like about the company is it brings me to unusual places," says Josie. "It's always challenging. In the past I've had to respond to pieces of art."

It's the weirdness of the idea of turning up in someone's living room and doing a show that she enjoys. That and the challenge of creating a show out of nothing. "I liked the idea of bringing a show to people who couldn't get to a theatre. It seemed like a lovely thing to do. So far nobody seems to have been mortally embarrassed by the whole thing."

To prepare for the shows she came up and visited all the people she was going to perform for and had a chat about what they liked. Hence the Dolly Parton covers for Janet.

Janet is 80 years old, loves musicals and can't remember the last time she had so many people in her living room. She's loved this afternoon, she says when the curtains have been opened, Steve the photographer has been and gone and things are getting back to normal. "What did she like best? "Oh Josie - And Dolly."

Even so, Janet has one small disappointment. No Daniel O'Donnell. She's hoping Daniel will come the next time. Grace may have some new songs to learn -

Trigger's Visit project continues this week with Karine Polwart making music for people with dementia.