Mrs Brown's Boys Christmas special inspired this year by Love Actually

For many, snuggling on the sofa and putting on the Christmas Day episode is as traditional as eating a mince pie. And amongst the millions of Christmas viewers is the man himself – and his family.

“We have a tradition that the family and some of the cast, especially the Ireland-based cast, all get into pyjamas and wherever they are they drive over to our house,” O’Carroll, 68, explains.

“And we all sit in our pyjamas watching the Christmas special on Christmas night, and Jenny [his wife who plays Cathy in the show] and I of course watch it like that,” he chuckles, hiding his face in his hands. “But it becomes a pyjama party and it’s a lovely night.”

Mrs Brown’s Boys, which airs this Christmas on BBC One, has had remarkable staying power in the saturated world of television, amassing millions of fans in the UK, Ireland and elsewhere.

Did O’Carroll ever suspect that he would become a Christmas staple?

“Absolutely not,” he says. “I swear to God. You know my mother always used to say to me, ‘You’re such a smart kid, Brendan. I can see in the future you’re either going to be prime minister or in prison, one of the two.’

“So I’m just delighted that I’m neither of those. That I get to be on Christmas Day, it’s beyond – you know people say to me, ‘God you must be living your dream.’ I am so far past my dreams that it’s just not right. My cup runneth over. It really does.”

And he is deeply grateful to the Mammy who has filled his cup.

On what he’d buy Mrs Brown for Christmas, O’Carroll starts with “a hot water bottle and a bottle of Irish whiskey” but that soon spirals and he spends the next five minutes waxing lyrical about the fortune the character has reaped on his family.

“Honestly, I’d buy her a villa in Spain and a Rolls Royce and get her her own jet so she could fly there any time,” he says, “because my god that widow has changed my life. She’s put my kids through school, she’s put my grandkids through school. She’s bought them houses.”

Mrs Brown’s Boys is certainly a family affair. The cast includes Winnie, Mrs Brown’s best friend played by O’Carroll’s sister, Eilish; his children Danny and Fiona who play Buster and Maria respectively; his wife, Jennifer Gibney, who plays Mrs Brown’s daughter, Cathy; his grandson, Jamie O’Carroll who plays Mrs Brown’s grandson. And so on.

The Christmas special sees the usual wise-cracks, snide Mammy comments and ridiculous moments that viewers love – with a side note of Christmas nostalgia and the unique gags the festive season offers.

Watching the film Love Actually is also one of O’Carroll’s traditions – “For Jenny and I, it’s not Christmas till we’ve seen Love Actually again,” he says.

And the iconic 2003 festive romantic comedy, directed by Richard Curtis also inspired some of this year’s festive episode.

“We give a nod to it in our own episode, and the story behind Love Actually has always inspired me because Richard Curtis, who has become quite a friend, told me when they were making it, it was a disaster, it just wasn’t working for them.

“And they decided to go back and shoot some more and make it a Christmassy theme. And now it’s a Christmas classic.”

But the episode is not all giggles. There are moments of poignancy and sadness, particularly the final segment when Susie Blake’s character, Hillary Nicholson, who has Alzheimer’s, sings a carol.

O’Carroll says he had been planning that for a few years: “How do I address something that’s so important and so common? And within a comedy show? Pathos is really important. But you have to earn it. And we earn it through comedy. We make them laugh, laugh, laugh, laugh, laugh. And then there’s that moment of pathos.

“I said to Susie, ‘When you stand up to sing the song can you sing it like a little girl?’ Because the people that I know with Alzheimer’s and with dementia, they remember every little detail of their childhood. They remember their first day at school but they can’t remember the name of the nurse who was in two minutes ago.

“So I wanted her to sing it like a little girl, as she would have sung it when she was a kid in the choir. And she did it absolutely perfect.”