"Sometimes I get irritated," Diane Von Furstenberg says with a tight smile, eyes hidden beneath huge sunglasses, even though we are indoors. And that, after 12 minutes of conversation, is the startling end to the interview.
You can't blame her: everyone wants a bit of Diane Von Furstenberg, and that day had been a prime example. Von Furstenberg had arrived at the Academic City campus of Zayed University to give a speech to the students about her life, her career and her wish to empower women. It was such a popular event that extra seats had to be called for, yet a number of girls had wandered out, BlackBerries in hand, part way through.
As soon as she had finished she was surrounded by staff and students desperate to have their photos taken with her, and then she was bundled off to a lunch that was supposed to be starting an hour later, leaving us hacks and snappers gawping in surprise, apparently bereft of our interviews. Dragged away from her meal early to do the planned interviews in a university corridor, it would have been no surprise had this 63-year-old fashion superstar, who by all accounts likes very much to keep to her timetable, been slightly put out. And what she really wanted to do was visit the gold souk.
There is no doubt that Von Furstenberg is a formidable woman, an indomitable designer and businesswoman. But tales of her personal kindnesses to friends abound, and in her public persona she exudes an ageless joie de vivre that makes her the perfect advert for her own colourful, easily glamorous clothes.
It is no coincidence that the best-known image of the fashion designer Diane Von Furstenberg is the Andy Warhol portrait created in 1974, in which her quintessentially glamorous face looks confidently back over her shoulder, eyes wide, lips bright red and glossy, a cloud of black hair emphasising those jutting cheekbones. If ever there was a person who knew a super-brand when he saw it, it was Andy Warhol. Campbell's Soup cans, Marilyn Monroe, Elvis, Warhol himself: those screenprint repeats became kind of unofficial logos for the genuine icons of the 20th century, the people and things that were so public that it seemed they could be entirely captured in a polarised, block-coloured image.
Von Furstenberg's name (her married name: she was born Diane Halfin in Brussels in 1947), her face and her story have been a brand for the 35 years that it has taken the wrap dress - her great sartorial invention - to come full circle from mass-produced must-have to over-saturated must-ditch and back again, once more a fashion classic of our time. (So very classic that during her speech at Zayed University she pulled up images of herself wearing a wrap dress 35 years ago in her first ever DVF photoshoot and Michelle Obama wearing a near-identical DVF wrap in the US first family's Christmas-card portrait last year.)
Von Furstenberg has a different kind of confidence these days. The twentysomething socialite who, with her then-husband, the late Prince Egon Von Furstenberg, epitomised the New York Studio 54 era, partying and playing while working and bringing up two young children (Alexandre and Tatiana), has become a revered figure of the fashion establishment.
She looks different too - as you'd expect over the course of 35 years - but there are none of the fillers and Botox to which so many beautiful women resort to maintain their youth. Von Furstenberg apparently likes her wrinkles, and is more interested in the person beneath - an unusual attitude for a woman who works in fashion, and perhaps one that is the prerogative of those with preternaturally marvellous bone structure.
"I'm still the same person," she says. "Yes, maybe I lived a little between 12 and 2.30 in the morning, and I was so serious in a sense, because you know I had children at home and I was separated and I was missing my mother. But I was working at 8 in the morning. I did go to Studio 54, but I never lost myself."
Like many of today's established designers, Von Furstenberg owes her success in some way to the great fashion editor Diana Vreeland, to whom she presented her pieces in New York back in the Seventies and under whose encouragement she found the confidence and the means to continue to make dresses.
"She was formidable and very daring and intimidating but wonderful," says Von Furstenberg, and she could easily be talking about herself. She did, after all, come back from a decade of fashion limbo in the Eighties, after her five million-selling wrap dress became passé, to become president of the powerful fashion trade organisation the Council of Fashion Designers of America (CFDA).
This is a strong woman, uncowed by personal or financial troubles, and she is very keen to share that strength with other women - something she calls "empowerment", a right-on American word that sounds just a little less glib in her Belgian-New York accent. She has established the DVF Awards to acknowledge female leaders and is a prominent member of Vital Voices, Hillary Clinton's charity that aims to honour women who make a difference in the world.
And while she's not exactly the media archetype of a feminist (a word that, for a younger, freer, more entitled generation, has become a slightly embarrassing anachronism), she is very happy to take on that mantle.
"Women in power: this is something that I care about. It's not a dirty word to me at all: I am a feminist - but it's become a little obsolete. To empower women is not necessarily to be a feminist; it's really to give women confidence about being able to realise their full potential - or what they think is their full potential, or what they want it to be. It's under no rule, except their own."
This is, in other words, about female confidence, and if wearing a great lipstick or a Diane Von Furstenberg frock makes a woman feel more confident then that's a very happy coincidence indeed. Well, maybe not a coincidence; let's call it a fortuitous synchronicity.
Her role at the CFDA allows her to exercise women's interests directly: she has been a staunch advocate of the promotion of healthy standards for fashion models, and now she is in a role with the power to influence the industry.
"Clearly you can imagine I always promote health," she says. "Good health is important to me, and there's no way that you can say that you want to empower women and then that you want them to be slaves in terms of weight - or even in terms of shoes. I don't want women to be slaves ever, or victims."
Certainly these are serious issues, but the glossy grooming, lithe figure, urbane New York manner and aloof sunglasses don't quite hide the fact that this is still a woman who conducts her life with every bit of energy she can master. At 63, she could be forgiven for pulling back from the constant travel, publicity and hard graft required to keep pushing the brand forward - for the launch of her Dubai shop, she has put in the hours with several events, dinners and so on to ensure everyone knows she's there - but in spite of having recently named a new creative director, Yvan Mispelaere (replacing Nathan Jenden), she remains very much the active face of DVF. And she looks extremely relaxed about it all.
"Relaxing is not..." she hesitates. "You know, my husband and I have a beautiful boat, so earlier this year when I was in the Gulf we were on the boat, and I sailed from Oman to Abu Dhabi. So I read, I swim, I hike, I have time to myself. But I have fun all the time. This is fun," she continues, waving around at the university campus. "I mean this is a great privilege, because you travel and you're not just a tourist; you also have a way to connect, and this was interesting to go inside a girls' university in the Middle East - it was madly interesting. And then when I finish my day I'm going to run to the gold market."
There's a lot still to fit in for Diane Von Furstenberg, and she's holding tightly, unstoppable to that schedule. It's probably wisest not to stand in her path.