VIDEO: Watch our exclusive backstage chat with Joanna Lumley - CLICK HERE.
ITV news reader Alistair Stewart, her celebrity interviewer, seemed for a moment lost for words as the packed theatre laughed, cheered and clapped with delight.
It wasn't any old bra but one she made into a pair of shoes to avoid getting trench foot while making 1994 documentary Girl Friday.
And she remains rightly proud of it to this day.She still carries it around in her bag, certainly when talking in public about her extraordinary documentary film-making career.
It sums up the actress turned doc queen who just loves to entertain and educate us all in her own absolutely fabulous way about the big wide world with her epic journeys to discover diverse cultures, continents and intimate portraits of pop icons from Elvis to will.i.am.
MORE VIDEO: Watch Joanna Lumley's full interview with Graham Walker - CLICK HEREThe former New Avengers and Bond girl, who started out in Coronation Street and Steptoe and Son, has gone on to appear in blockbusters like Wolf Of Wall Street.
But absolutely adventurous Joanna was invited to Doc/Fest to talk about her documentary experiences, making the likes of her Trans-Siberian Adventure, the Northern Lights and travels along the Nile, as well her future documentary work, which will next take millions of viewers with her to Japan.
Before that we caught up with her backstage and asked her about her career including the documentaries but also her forthcoming Absolutely Fabulous movie, out in cinemas on July 1.
In an exclusive chat - watch the full interview on our YouTube player - she laughed out loud when asked how she stays so absolutely fabulous and sexy at 70.
"That's so kind," said Joanna, who celebrated the landmark birthday just days ago.
"I think liking stuff, liking other people; being interested. Keeping fit. By that I don't mean going to the gym, because I never do that.
"But don't eat too much. I'm a vegetarian, which I'm sure keeps me healthy, so you are healthy and you are lively. And be interested in the world. I think that helps. If you are always curious about people and about places and how to make stuff better, that makes for a good life. Because every day is brand new with a great adventure ahead of it. Even if you are not making documentary films."
Joanna isn't new to making documentaries. As long ago as 1991 she travelled to Malaysia to explore the legacy of the legendary British rulers of the jungle kingdom of Sarawak for the film In Search of the White Rajahs and was memorably sent by the BBC in 1994 to a desert island in Madagascar for a week for Girl Friday.
"It seems to have been an amazingly long career, making documentaries. When I count them up and go backwards, it goes back a long, long time," she said.
"And I've had the best time of my life, really, making documentaries, going all around the world, from the Northern Lights up in the Arctic Circle to down top orangutans in Borneo and following the length of the Nile, going all the way around Greece and Africa, doing stuff.everywhere."
She added: "I've just finished doing Japan, which is a documentary for later in the year.I think it's coming out may be November. It's thrilling. We all think we know quite a lot about Japan because we know sushi and words like tsunami and sake. We buy Japanese cars and so on. But we, or rather I, knew so little about it.
"There are 4,000 islands, 100 active volcanoes and the main part of Japan is four islands. It was going all the way from the very top, in deep snow or an ice-breaker ship, coming down gradually through to the cherry blossom over volcanoes and things like this, right down through extraordinary Buddhist walks through woods and things, right down, trailing off to the south - a 2,000 mile journey, talking to the most fascinating people."
Did she learned anything about travel documentaries and celebrity interviews from Sheffield's own comedy genius turned travel master Michael Palin and Barnsley's chat show king Michael Parkison?
"Absolutely," she said, as only Joanna could, in that soft, sincere and heart-warming voice which is instantly recognisable and has won the hearts of the nation and beyond.
"I've been a guest on Parkinson several times and I know the two Michaels. I also used to stand in for Terry Wogan and interview his guests when he was away on holiday.I had the great honour of speaking to Muhammad Ali.
"Michael Palin is always a step ahead of me. He was going across the Himalayas and I was going, ' no Michael, I was born in the Himalayas. And he went, 'ha,ha...I'm doing it', So he's just a legend going ahead of me.
"They are always inspirational;. They both displayed huge curiosity about the people they were talking to , so they ask in the spirit of true inquiry. So you don;t come with a fixed, closed idea of what's going to be. You are open to suggestions. And of course the great David Attenborough, who is also coming to Doc/Fest, the guru of all."
She also spoke about her forthcoming Absolutely Fabulous film, a spin-off of the TV show, which will feature her back as fantastically louche fashionista Patsy Stone, with all its lead characters including co-star, series creator and writer Jennifer Saunders, who plays Edina.
There is also a huge cast of celebrity cameos and Joanna said it was 'fantastic' that Kylie Minogue has re-recorded This Wheel's On Fire, just for the film.
She said: "It's got the same five core members, all of us in it, a lot of people who have already been in the show and about 60 who have never been in it, huge stars who are just drifting through, sometimes with insulting small parts, all taken by them with the greatest good grace.Just enormous fun.
"It's got a sort of a chase line running through it.I think you know by now that Edina and her grasping nature, rushing to get Kate Moss and manage to kill her, knocking her into the Thames.It's partly a police chase thing. It's just funny and ridiculous.
"It think it's like a glass of champagne on a summer evening."
What would Patsy make of being at the prestigious and now world renowned Sheffield Doc/Fest?
"Patsy was brought up rather like an ally-cat, all over Europe. She's sort of Euro trash, so she would feel she knew all about a different kind of Europe," laughs Joanna, slightly turning up her lip in her Patsy guise.
"From the darker side of Europe, maybe the drug dealers, the huge celebs, the unnamed 'princelings' and people like this, the rock stars of those countries. So perhaps Patsy would have a different take on it. She wouldn't really remember much about it, I wouldn't think."
Joanna confessed that she does quite easily slip into Parsy during day to day conversation.
"She's quite near me all the time," she giggles. "Particularly now, when she's come back with a vengeance."
Wildlife king Sir David Attenborough, Kes director Ken Loach, cricket great Freddie Flintoff and snooker star Ronnie O’Sullivan will all speak at Doc/Fest on Monday, June 13.
Chariots Of Fire director Lord David Puttnam and Doncaster born film producer Mark Herbert, head of the Sheffield-based production company Warp Films,who produced Four Lions, Dead Man's Shoes, and TV comedy Phoenix Nights, will speakat Doc/Fest on Tuesday, June 14.
They follow Oscar winning documentaries king Michael Moore and TV's Louis Theroux, who spoke at the weekend.
Doc/Fest, now one of the world's leading documentary festivals, will screen 160 international and UK documentaries, 27 world premiers, 15 international, 19 European and 52 UK premiers.
For more about Sheffield Doc/Fest, which runs until Wednesday, June 15, see the official web site at sheffdocfest.com