I love the adventure of touring with Mrs Brown'

However, female fools have been rather more thin on the sitcom ground (male writers' fear of sexism?), with only the likes of The Vicar Of Dibley's Alice Springs, Ab Fab's Bubble and, going back a bit to find the ideal airhead, Nearest And Dearest's Nellie Pledge, being shining examples.

Now, there's a new sitcom heroine who can sparkle among the dim. Mrs Brown's Boys' Winnie McGoogan is the perfect stooge for the caustic Agnes Brown, a lady who can take the put-downs in her stride. And the actor who plays Winnie, Eilish O'Carroll, is certainly smart enough to get the nuance of the TV clown just right.

The blonde Dubliner, stylishly dressed and a million miles away from Winnie McGoogan's slippers, collapsed tights and wholly unflattering headscarf, is also a writer and has created her own autobiographical show. Live, Love, Laugh is set to run at the Edinburgh Festival Fringe, a revealing story that's warm, sad and very, very funny.

"I wrote it last year and performed the show in Belfast, and it went down really well," says O'Carroll. "But I've been reworking it since for Edinburgh, and hopefully this show will hit the mark."

The writer takes the audience on a remarkable journey, from growing up in North Dublin housing estate Finglas as one of 10 kids to becoming a stage actress, to two failed marriages and coming to terms with realising she is gay.

"I suppose I've been acting all my life," she says with a wry smile. "It began when we were kids. With so many of us you had to stand out. We were all competing for attention."

O'Carroll could never afford to even dream of life in performance. "Secondary-school education in Ireland at this time had to be paid for, so I left school at 12 and went to a commercial college. And times were so difficult it was assumed the girls in the family would all move abroad to find work, a husband and hopefully a better life."

O'Carroll and her four sisters all emigrated (the boys in the family, including Brendan, the Mrs Brown creator and star, stayed at home, to work in the catering industry) but a 
hoped-for Canadian dream didn't materialise.

"I didn't want to go to Canada when I was 17. And when I got there I was homesick and miserable. So I returned to Ireland, married a Northern Irishman and then moved again, this time to live in Surrey, aged 20."

Meantime, her marriage broke down. If it weren't for the fact she now had two sons, it would never had lasted eight years. However, escape – and fun – emerged when she joined the local dramatic society. "I loved it," O'Carroll recalls. "And I was involved in a musical group called The Pentagon for a few years. There were only four of us after one left, but we didn't bother to change the name."

In time, O'Carroll met another man but, by the age of 40, had begun to question the very point of life. She felt lost. She needed more. But what? In her stage play she explains how she came to realise she was gay.

"Now, it may sound like I went looking for a pair of shoes lost in the recesses of my wardrobe, and lo and behold I found not only the shoes but a lesbian wearing them. No, it wasn't like that. You see, I met this woman, as you do, straight, and like me also searching for the meaning of life. We met at one of those workshops where you find yourself through spirituality. And while we didn't find the meaning of life, we found each other."

For a while. The relationship crumbled and O'Carroll ran back to Ireland "to hide". Aged 45 she joined the circus – or rather the troupe of actors her younger brother Brendan had formed, and toured with his second comedy play Grandad's Sure Lily's Still Alive, as a wardrobe mistress.

When her younger brother came up with his first Mrs Brown play in 1999, O'Carroll joined the cast playing Winnie.

"I based the character on a friend of my mother's, a lady called Nancy Pimley. She wasn't stupid like Winnie, but she was a bit in awe of my mother, who 
was very clever. But I love playing this woman who doesn't quite 
get it.

"I've always loved watching the great fools," she adds. "I was a huge fan of Norman Wisdom. And I do like Alice in The Vicar Of Dibley. I think there's a real joy in playing one of life's innocents. Julie Walters can also do it so well."

O'Carroll was clearly born to the stage, and it offered added delight. In 2003, she met her partner Marian, who works in production with the Mrs Brown stage show. "She's a lovely lady and my sons and ex-husband adore her."

O'Carroll's stage show evaluates the vast changes in her life, from the process of sexual evolution to the incredible change in fortunes now that Mrs Brown's Boys is a global phenomenon.

"How do you measure life changing?" she wonders. "If it's by the celebrity status then my life hasn't changed. I don't get recognised which is a great thing, unless I appear on a talk show in Ireland. But I love the adventure of touring with the Mrs Brown team, of working with my little brother. The genius of Brendan is he can take audiences on a rollercoaster. And you go along with him. But at the same time, it's surreal to see myself on screen. I find it hard to watch myself."

She won't find it hard to appear as herself on stage.

"I feel it's what I've always wanted to do," she says of her show. "And this time around, the audience will get me. All of me."

And perhaps a little bit of Winnie? "Maybe just a little of her voice," she says, smiling.

Live, Love, Laugh is at the Pleasance Courtyard, Edinburgh, July 31-August 24.