“I was indulged by a large number of aunties,” he admits. “On Sunday afternoons, I had to perform a little cabaret. There was a camphor box – I still have it – in which I kept a sailor suit, a Chinese outfit with a hat and a pigtail, a Red Indian suit and a diverse range of costumes.”

It may have been an early clue to his future career on stage, but there was no sign that one day he would become the world’s most famous female impersonator.

In fact, the coruscating wit, boundless self confidence and outrageous cheek that epitomised his creation Dame Edna Everage were still many years in the future.

“I’d appear and they’d all laugh and clap and then my mother would urge me to sing Nymphs And Shepherds,” Barry recalls. “But I was too shy and had to go behind the curtain. Then she would say, ‘Pretend to be the wireless, darling’.”

The little boy would go on to build an entire comedy career around pretending to be other people.

But now, at the age of 88, he is about to embark on a new one-man UK tour, and for once, Dame Edna’s sequinned frocks – and the foodstained ties of crass cultural attaché Sir Les Patterson, his other alter-ego – will remain in the dressing up box.

For the first time, Barry will be doing an entire show as himself. Both his monstrous creations may make brief appearances on stage in film clips but essentially the evening will consist of the Australian legend sharing anecdotes and observations from his crowded life, both professional and personal.

By the time he opens in Nottingham on Thursday, he won’t have been on a stage for nearly three years. So it promises to be quite a brave, not to say exposing, undertaking.

Is he scared? “Oh no,” he insists. “I’ll get back in the groove very quickly.

“There will certainly be no shortage of on material. We meet in the north London mansion flat where he’s lived with his fourth wife, Lizzie Spender, daughter of the late poet Sir Stephen Spender, for more than 30 years now.”

And Barry is in reflective mood, able to conjure at will pin-sharp anecdotes from years ago. Like the time he lobbied for an honorary military rank.

After vate school, he had to do National Service with the Australian army. “I was a private in the Melbourne University Rifles. The regiment still exists to this day. They wrote to me not long ago inviting me to speak at a big reunion dinner. They explained they couldn’t pay me but that, if there was anything they could do for me, I had only to ask.

“So I wrote back saying I didn’t want a fee but I was interested in rank. Would they please elevate me to Brigadier? I didn’t think it was too ambitious a request: I wasn’t asking for General or Field Marshal.

“I had a vision of walking into a restaurant and the head waiter saying, ‘Show Brigadier Humphries to his table.’ I heard not another word from them.”

But he’s managed pretty well as plain old Mister Humphries.

His life, he says, has been embellished by a rich array of the great and the good.

“I’m so lucky,” he says, “to have known so many interesting people.” Among them the great painter Augustus John – “What a scruffy old dotard he was!”

He also knew the late poet laureate Sir John Betjeman and the art critic Sacheverell Sitwell. As a young Australian moving in such exalted circles in London he felt rather out of his depth.

“The Sitwells and the civilised world they inhabited seemed as remote to me as the Aztecs,Troy, Nineveh,” he says.

In New York, he met surrealist painter Salvador Dali and his wife, Gala, who invited him for afternoon tea at the St Regis Hotel.

“I was very highbrow then; not so much now. I had no real interest in pop music.”

Did that extend to the Beatles? “I met them, of course. Ringo Starr I liked best of all. The politest person I’ve ever known was David Bowie. He had such good manners and he was very flattering. He insisted on calling me Sir. It felt a little ageing but it was very respectful. I regret not getting to know him better.”

Barry’s successful TV show in the 1980s – hosted by Dame Edna – attracted many big names. “Lauren Bacall, who became a good friend of mine, was one of them, as was Tom Jones, a very popular guest.

It took some courage to appear alongside Edna who, by this stage, had lost all her inhibitions and was inclined to say exactly what was on her mind.

“She had a hot seat and, if she took against someone, she’d press a button and they’d be tipped backwards, a device that has since been stolen by Graham Norton with no hint of an apology, still less a royalty.”

Barry also befriended pop star Leo Sayer when he was topping the charts.

“And I’ve recently reconnected with him in Australia where he lives. He’s a lovely fellow. I remember we were both presented to the Queen after a concert at Windsor Castle in 1975. It was the first time I’d met her and I found her very pretty although rather shy.

I think she was a bit intimidated by this giantess of a woman. I’ve been presented to her on a number of occasions since and I’m a big fan.

“She’s magnificent. I will hear not one word against her although her sword has yet to descend on my shoulder, of course.”

It could still happen. “I’ve just been naturalised so I now have dual Australian and British citizenship,” Barry points out.

Where does he stand on Meghan and Harry? “To be honest, I no longer think of them as royal,” he says.

“When I see how hard Prince Charles works and what a fine example he sets, I find it vicariously painful to witness the rift that seems to have taken place between father and son.”

Barry himself has two daughters from his second marriage to actress Rosalind Tong and two sons, Oscar and Rupert, from wife number three, Australian artist Diane Millstead.

“Between them, my children have produced 10 grandchildren on whom I dote.”

How does he account for the success of his fourth marriage, to Lizzie?

“I’m much smarter now. For over 10 years of my life, I had a serious alcoholic illness. I finally put the cork back in the bottle in my late 30s and haven’t touched a drop from that day to this.”

About four years ago, there was a brief wobble in Barry’s relationship with Oscar, 40, whose tweets, says his father, grew a little wild. “But that all blew over relatively quickly. I think Oscar was feeling a bit hard done by but we’re very good friends today.”

A one-time editor of art magazine, Apollo, Oscar is currently a curator of exhibitions, living in London with his wife, Sophie, and their two children. Rupert, 38, a writer of video games, also lives in London with his wife, Olivia, and their three youngsters.

“How I feel about my grandchildren is how I wish I’d felt about my own children when they were born,” Barry admits. “At the time, I was too wrapped up in myself and my work. I’ve always liked Noel Coward’s observation that work is more fun than fun.”

Am I looking at a happy man? “Oh yes. I’ve learnt to live in the present, a very hard thing to do but a very good spiritual exercise.”

Performer, painter, caricaturist, writer, Barry Humphries could accurately be described as Renaissance Man, a compliment he quickly waves aside.

“No, no, I’ve been too much of a dilettante,” he protests.

He’s being unduly harsh on himself: dilettantes dabble. A reluctant smile. “Well, yes, I suppose you could say I’ve done a bit more than dabble.”

Barry Humphries: The Man Behind The Mask. Tickets available here.