London, United Kingdom—Older women are fronting major fashion campaigns and one of the next Bond girls is 50 -- mature ladies are having a moment, but does it represent a change of attitudes or just a marketing gimmick?

With her silver hair styled into a severe bob, clad all in black with huge sunglasses, 80-year-old US author Joan Didion cuts a striking figure in the new ads for Celine.

A guitar-strumming, floppy hat-wearing Joni Mitchell, 71, fronts Saint Laurent's Music Project, and Dolce and Gabbana focuses its new campaign on cackling Italian grandmothers.

Meanwhile Madonna, 56, has been posing for Versace, Julia Roberts, 47, is the face of Givenchy and Italian actress Monica Bellucci, 50, will soon be the oldest ever Bond girl.

Such adverts should be no surprise given an ageing population and the growing purchasing power of older people in some parts of the world.

The senior market is "one of the most powerful consumer groups in mid to long-term", said Magdalena Kondej, an analyst for Euromonitor International.

"Marketing targeted at elderly consumers that has found success to date often uses older celebrities in advertisements," she said, citing L'Oreal's recent signing of Jane Fonda, 68, to advertise a face cream for over 60s.

"This approach would also seem the best option for apparel brands and there is no shortage of poster girls for older, glamorous women,"  Kondej added.

But critics question whether this signals a real change in attitudes, or are simply the latest shock tactics by a fashion industry that will never give up its love of youth.

- 'Makes a nice contrast' - 

Sylviane Degunst, 56, was spotted by a model scout two years ago on a London street, and has since appeared in photo shoots for high-street clothes as well as other adverts.

Slim, although not tall, she has killer cheekbones and hair that has been white since she was 18. 

Degunst was a writer and publisher in her native France, but struggled to find work on moving to Britain and has embraced her new career.

"I can't use my mind any more so I may as well use my old body... I'm having a great time!" she told AFP.

"We're not in competition with the young girls, but I think it makes a nice contrast. It's interesting to mix things up."

Degunst is far from the top end of the age spectrum -- American Carmen Dell'Orefice is still modelling at 83 -- but she says that stereotypes still prevail.

In one of her first modelling jobs she was asked to sit in a wheelchair, while in another, scouted because of her white hair, she was rejected because she did not look old enough.

Artist, writer and curator Sue Kreitzman insists that older women are becoming more visible in all public spheres, and even goes so far as to call it an "older lady revolution".

"It's happening slowly, but it really, really is happening," said the 75-year-old London-based New Yorker.

Kreitzman praises the Celine pictures for showing "that older people are here, we're beautiful -- we count".

"What I love about it is that Joan Didion doesn't look the slightly bit young. She's gorgeous and she's an old lady," she told AFP.

On the catwalks, even if former supermodels Amber Valletta, 41, and Eva Herzigova, 42, both took to the runways in Paris in January, skinny young women still rule.

But Sylvie Fabregon, who runs the Masters and Silver agencies for older models in the French capital, says she is seeing increased demand for more mature women.

"People are not stupid -- women have had enough of seeing 20-year-old girls in adverts for cosmetics to fight wrinkles they don't have," she told AFP.

- Marketing gimmick? - 

Many Western countries are seeing a growth in the "grey pound", not least Britain, where pensions have been largely protected since the financial crash while wages have stalled.

In 2012, the over 50s accounted for almost half of all UK household spending -- and spending on clothing is soaring, according to the Centre for Economic and Business Research.

Sandra Howard, a 74-year-old author who was a top model in the 1960s and 1970s, is sceptical about the new trend, saying the fashion ads featuring older women are "not about grey power, but the power to shock".

"It's one thing to have a beautiful older woman in a cosmetics ad -- I think that does work," she told AFP, citing "The Queen" actress Helen Mirren's campaign for L'Oreal.

"I think in fashion photography you can mix in older and younger women, I think that's good. But if you go too much and do it as a gimmick, it's slightly offensive really."

However, she concedes things have moved on a bit. "When I was modelling, you were old when you were 30!" she laughs.