A fan of clean, pure lines, her look projects a formal elegance with some very deliberate decorative Chinese flourishes; her image brings a chic touch to the dour face of Chinese politics.

At the opening ceremony of the 2014 Nanjing Youth Olympic Games, Peng stood at her husband's side as he greeted UN Secretary General Ban Ki-moon.

During a visit to the Nanjing Museum, where she accompanied the wives of visiting heads of state as they tried their hand at Suzhou embroidery, Peng wore a pale yellow outfit and a light grey scarf.

The photo op was also an opportunity for soft diplomacy, as it showed a rare gathering in China of high-profile women from around the world. Peng's outfit conveyed something fresh, serene and positive.

Peng appears to like structured clothing. Tailored jackets, nipped in at the waist, seem to have become a favourite of hers. She also likes modernised Chinese qipao dresses, Chinese floral motifs and mandarin collars - a stylistic statement and a strong visual theme for her brand of "soft power".

For better or worse, the fashion sense of women in diplomatic circles has long generated public interest. The same does not apply to men in politics, and the double standard remains a point of contention for the likes of former US secretary of state and first lady Hillary Rodham Clinton, whose hairstyle recently came under scrutiny.

And who can forget how Clinton's blue pantsuits and former US Republican vice-presidential candidate Sarah Palin's red skirt suits almost took on personas of their own during the 2008 elections.

First ladies, whose roles are different to those of female politicians, have more willingly acknowledged their roles as style ambassadors.

Consider how US first lady Michelle Obama's love of Jason Wu and J. Crew boosted those brands. Samantha Cameron, the wife of British Prime Minister David Cameron, did the same for Roksanda Ilincic and Erdem.

Then there is the "Kate Middleton effect", the effect that Britain's Duchess of Cambridge has had on British spending on domestic fashion labels such as Alexander McQueen, Issa London, Mulberry, Temperley London, as well as smaller boutique brands.

If Michelle Obama has Jason Wu, Peng has mainland designer Ma Ke, who has been personally designing for her for more than a decade.

While giving a boost to home-grown designers such as Ma (who heads the Exception de Mixmind label, as well as couture line Wuyong), Peng's structured and unfussy wardrobe could be seen to reflect Xi's drive to clean up the ruling party.

Her own public image as a folk singer and performer adds a glamorous flair hitherto unseen in high-profile women in China's ruling political class.

During the couple's visit to Seoul in early July, Peng's stylish button-down long white suit, white clutch, and green floral brooch made for a positive and pure look.

In May, she met Russian President Vladimir Putin at the fourth Conference on Interaction and Confidence Building Measures in Asia summit in Shanghai; she wore a black tailcoat style jacket, and a graphic batik print, white and navy qipao. She was later seen in a modern floral print qipao with another well-cut jacket.

The fascination with Peng's style started early on. In March last year, during Xi's maiden overseas trip as China's newly elected president to meet Putin, and African state leaders, there was almost as much interest in Peng's style as Xi's agenda.

When 51-year-old Peng emerged from the plane alongside Xi in Moscow, wearing a tailored double-breasted dark blue trench, she sparked a flurry of internet activity back home.

Her chic, conservative ensemble of dark trench, pale blue scarf, black knee skirt, modest lace-up heels, and a simple black handbag was hardly groundbreaking for Western observers.

But on the mainland, where there has been a distinct lack of female glamour at state events, Peng's style came as a revelation, and a timely symbol of home-grown soft power.

"That belted coat incorporates elements from classic military uniforms of the West and gives a crisp look with elegance," Xie Ping, a lecturer from Beijing Institute of Fashion Technology, told Xinhua.

An online frenzy ensued on Chinese e-commerce site Taobao, as copies of her outfit sold fast. For a while the topic was so sensitive that key search terms about her fashion sense were blocked by mainland internet censors.

Sharp-eyed fashion bloggers identified the trench coat and handbag as being from Ma's Exception de Mixmind label, which was then hip, but not well known. The visit gave the brand a big publicity boost.

It's not just the Chinese who have become obsessed with Peng's sartorial leanings. listed Peng in its annual best-dressed list of 2013; Michelle Obama was not included. The same year, magazine also listed Peng in its 100 most influential list, in the icons section.

When she and President Xi welcomed their first international head of state, President Francois Hollande of France, in 2013, Peng's form-fitting, structured black jacket, black-and-white skirt, and matching pocket handkerchief again drew attention and praise.

The intense analysis lavished on Peng by fashion observers is something she'll have to get used to. The Obamas' visit to China in March this year set off "fashion face-offs" in the media between the two women. It's hard to imagine that, only 18 months ago, Peng was unknown to those outside China.

At home, Peng's penchant for home-grown brands is stimulating discussion because most young people in China crave luxury Western fashion. In a forum on the online version of , one user said, "Peng's preference for a Chinese fashion label will help to guide domestic consumers away from the obsession for Western luxuries."

Since Chinese internet users have played a major role in "outing" civil servants for their excessive love of Western luxury labels, the importance of Peng's presentation is not to be underestimated. By eschewing the usual monogrammed goods by European luxury giants that are loved by many Chinese, Peng is sending out her own message: her serious, structured, chic style, which is offset with a decorative flair, is significant in this regard. She may help turn the tide towards home-grown fashions in China.

In the wake of Peng and Xi's inaugural visit abroad, some Chinese fashion and accessories companies reported an increase in sales. has also noted the positive effect Peng had on China's bespoke tailors. These are just the first signs of her growing commercial clout.

How is she coping with her newfound sartorial power? Peng is no stranger to the limelight, as the soprano was known for her patriotic songs, and was a household name in China before Xi rose to power. Peng was appointed the director of the Song and Dance Ensemble at the Political Department of the People's Liberation Army in 2009.

As Xi ascended power, Peng shied from the limelight to prepare for her new role as the spouse of a future state leader.

Now that Peng's role has fully shifted from a folk song diva to a national fashion icon, her stylistic influence is set to grow even further. The question now is whether other well-positioned women in Chinese government circles will follow her lead.