THE Dolls are taking over the world. Or at least the world that is Scottish theatre. The relatively unknown – certainly to mainstream audiences – comedy double act has been selling tickets faster than your granny grabbed washing off the line at the first spit of rain.

As soon as their 13-date tour was announced, Motherwell sold out in an astonishing seven minutes, Falkirk in eight. The King’s Theatre in Glasgow took 52 minutes but that is, after all, an 1,800-seater auditorium.

Since then, extra dates and venues have been added, such as the 3,000-seater Edinburgh Playhouse, Europe’s largest theatre.

Who is behind this phenomenon? How did The Dolls’ characters – Glasgow cleaners Agnes and Sadie, who are always on the hunt for men, drink and men (they like men) – develop into the most popular stage double act since Francie and Josie? What is there about The Dolls that attracts 30,000 followers on Facebook and pulls in three million YouTube hits?

The Dolls are Gayle Telfer-Stevens and Louise McCarthy. In their other professional lives, Telfer-Stevens, from Renton in Dunbartonshire, stars in BBC soap opera River City while Maryhill-born McCarthy is a luminary of the National Theatre of Scotland, starring in John Byrne’s comedy Cuttin’ a Rug.

The women are at the top of their game but a year ago they were playing working men’s pubs. Go back five years and they had both fallen into a career sink hole. And it’s from that chasm The Dolls emerged.

“We met at a one-nighter musical theatre cabaret show at the Tron Theatre in Glasgow in 2011,” recalls Telfer-Stevens, 36, in her River City dressing room. “Things weren’t going too well. We both had gone to musical theatre school in Glasgow and London, and landed the big West End jobs. I was in The Jerry Springer Show and Louise in Mamma Mia!, but then it all went tits up for me.”

The actress grins and adds: “I was so desperate I applied for teacher training at Aberdeen, the only f*****s that would take me. I just wanted to be a normal person, pay my bills and get a house and a motor. And I went up there, sat in a lecture theatre and thought, ‘Naw, this isn’t for me.'”

McCarthy takes up the story. “I was soul destroyed after Mamma Mia! I was ready to give up the business. I remember going up for a job in the Met as a policewoman. I actually went up to the building, walked in to the foyer and thought, ‘Bugger this,’ and walked out. But I was lost.”

McCarthy returned to Scotland, auditioning for work which led to the Tron gig. The pair were instantly impressed by each other’s singing talent. But there was more of a connection.

“I realised we were both the same, both working class,” says Telfer-Stevens. “We were artistes, yet wanted nothing to do with all that [posh voice] luvvy-darling stuff that gives me the pure boak.”

McCarthy, 29, admits she too suffers from the pure boak at the very hint of pretentiousness. “When Gayle walked into that dressing room and told a joke about a lassie going out on the mad wine, getting off with a bloke and waking up next to his pal, I said to her, ‘Ah feel Ah pure know you!’”

A bond was forged. Sisters separated at birth. Not twins. Telfer-Stevens is a brunette, 5ft 11in and a big girl (though less big since the recent diet). McCarthy is blonde and 5ft 4in. But when it comes to connection they make Frozen’s Elsa and Anna seem remote. They make Fran and Anna look like passing strangers.

Meanwhile, they had to to pay the rent. Telfer-Stevens took a job with John Lewis Direct, booking in washing machine deliveries. “I was so bored we used to try to get the word 'bawbag' into the conversations.”

She took off to New York to find herself via an acting course and came back pregnant. (Her daughter Stevie is now five.) Meanwhile, McCarthy worked in restaurants and in desperation decided to sing for her supper. She bought a microphone, a CD compilation and the one-time London star toured the Glasgow pubs singing Sweet Caroline and Patsy Cline’s Crazy.

The pair, however, had kept in touch. Telfer-Stevens was working as a chambermaid in Cameron House Hotel on Loch Lomond which later gave them material for their act. They both yell in harmony, "House keeping" – a line from their stage characters.

“We threw around the idea of singing together, because we loved the old-school musical sound,” says McCarthy. “We thought of being two Ethel Mermans. Then we thought we’d do Motown, so we learned 30 songs we needed for a pub set. But I knew this would be knackering on the throat.”

Telfer-Stevens says: “That’s when we thought about adding talking to the act. Sketch comedy. So we came up with the idea of playing a couple of cleaners called Agnes and Sadie.”

McCarthy adds: “There was another reason. If you did a singing gig you got paid £150. We discovered if you do comedy as well you get £400.”

They had no comedy ideas. Nothing. What they both had was a role model in actress, comedian and entertainer Dorothy Paul, who’d also played a very funny cleaner. Telfer-Stevens attended Paul’s drama school, aged eight. “She was the reason I wanted to become an actress.”

Full of the desire to channel their inner Dorothy they approached a booking agency. Their first gig was at a Masonic club, one Sunday night.

Telfer-Stevens says: “The convenor wore a blue, red and white tie and there were pictures of the Queen everywhere. I thought ‘What the f*** is this?’ I had never seen anything like it and I’m a Proddy.”

On the day, the Masonic club virgins turned up at three in the afternoon, all prepared, sound checked and wired. They were both nervous wrecks. McCarthy bursts into laughter. “I was terrified, and we had to get dressed in the kitchen because there was no room anywhere. And there we were in costume and the road to the toilet was heaving with stuff and I was burstin’ – [now she can’t speak for laughing] – so I used the sink.”

Telfer-Stevens plays down the impromptu bladder release. “You just couldn’t use most of the toilets in these gigs. We had to use paper cups, all sorts."

The night went well. “We told stories about men, and stuff that we heard from my granny,” says McCarthy. “Like the story she’d heard on the bus: a wummin saying she had been burgled and that the burglar had s*** in her mince. Her pal says to her, ‘Oh my God, that’s terrible. Whit did you dae?’ and the wummin says, ‘Ah know. I had to throw hauf of it oot.’”

The Masonic audience loved the tales about the likes of sex-starved Channel Four Sandra, so called because "she’d been round the scheme more times than the Secret Millionaire".

The second gig, however, which took place in Motherwell, looked doomed from the moment they walked in to hear a punter say, "Are youse funny?" And another one chimed in, "Ah hope so. We had a bloke in last night daein’ a Billy Connolly and he wis brilliant."

The girls weren’t brilliant that night. They died a slow death. Then the bar owner didn’t want to pay them. “This woman with Cash Converters jewellery and frosted pink lipstick asked for a discount,” says Telfer-Stevens. “I said, ‘I’ve got a baby to feed.’ We got the money eventually but we sat in the car park until four in the morning, greetin’.”

McCarthy says: “We weren’t their cup of tea. The crowd was older, and we were a bit too risque.”

The Dolls, it has to be said, use their rubber-gloved hands to explore every area to find comedy. Sex is described in graphic detail. It’s perhaps not a show to take your granny to, unless your granny loves to hear male and female genitalia described in a dozen different ways.

Telfer-Stevens says: "We’re no cheekier than the Still Game boys. It’s just that women doing rude stuff isn’t always so acceptable, not in an older crowd anyway.”

After the Motherwell disaster, they played bowling clubs and working men’s clubs, and improved. Then they began to book their own gigs, in clubs which were age and sensibility appropriate, when they realised one agent was paying them less than he should have been.

They put leaflets through doors. They told pals. The Dolls came to life. “Clydebank was the best moment I’ve had on stage, including Mamma Mia!,” says McCarthy.

Posters would go up on a bowling club wall on a Friday and by the Saturday the show would be sold out. They changed the act. They dolled up in sparkly frocks for the second act and sang parody songs. They threw in a raffle, offering tinned chopped ham and pork as the prize. They put videos up on YouTube and got more hits than a fairground hammer.

During weekdays they would audition for straight acting work. “We were keeping The Dolls under the radar,” says McCarthy, anxious that theatre or television producers would judge them. And some did. One told McCarthy’s agent he wouldn’t see her because she was “all tits and teeth”. He was talked into auditioning her and admitted he’d been wrong.

McCarthy joined the National Theatre of Scotland, stealing the show in productions such as Yer Granny, with Gregor Fisher. “I remember telling Gregor I did gigs at the weekends with my pal. He was taken aback, but said, ‘You know, that is the best training you will ever get as an actress.'”

Telfer-Stevens landed River City and became a storming success playing Caitlin, the benefits scrounger.

Meantime, The Dolls developed their sketches into a play, The Dolls Abroad, a very earthy farce which involves winning a holiday trip to a Greek island, a little drug muling and a kidnapping.

When they staged it for a week at the Mitchell Theatre in Glasgow last year it sold out and was seen by producer Robert C Kelly.

He says he had to take them under his aegis. “They were so good and so popular it made total sense to take them into Scotland’s major theatres,” he says, “but neither myself nor the girls can believe how successful ticket sales have been.”

TV comedy producers, however, have been slow to come knocking – despite both showing they have the comedy chops to work on television, having appeared in BBC Scotland’s Sketchland.

“We’ve always had to do it all ourselves. Maybe we’ll end up making our own show,” says Telfer-Stevens. McCarthy agrees. “We can go straight to Netflix,” she says, smiling.

There’s little doubt the act will grow. (They would be a stick-on for a TV Hogmanay show.) They have a great work ethic and they know their audience because they are their audience.

The filthy cleaner act works not just because they are funny but because they are each other’s biggest fans. They have a great chemistry and a great friendship, highlighted by how often they tease each other. “I remember you pouting in the Tron mirror putting foundation on your lips to give them sheen,” goads Telfer-Stevens. “Shut up,” McCarthy ricochets back.

But surely it hasn’t always been so cosy-comfy? Two big personalities often add up to a bit of fur flying. Do they ever throw the plastic coffee cups at each other? “Yes, full of p***!” jokes McCarthy and they both scream with laughter. “But opposites work. We’re very different personalities.”

Telfer-Stevens kicks in. “There was a time when on stage we were competing for the laughs but that settled. We now give each other the best lines.”

Great. But do they ever fall out? “Oh aye,” says Telfer-Stevens. “And we cry a lot. It’s really stressful in rehearsals. We feel the pressure.”

“But we de-brief,” says McCarthy. “Every night after rehearsals we phone each other for 15 minutes.”

“It’s no’ 15 minutes, she’s a f****** liar,” says her chum, laughing. “We need that length of time to sort stuff out. But at the end of every night we always say: ‘I love you.’”

The Dolls Abroad tours Scotland from March 17. Visit wearethedolls.com