China's next first lady Peng Liyuan is a dazzling singer whose profile long eclipsed that of her husband Xi Jinping, and who will bring a touch of glamour to a role hidden in the shadows for decades.

Xi is due to take up the leadership of the Communist Party at the close of its congress this week and comparisons are already being drawn between Peng and Carla Bruni, the singer and model who wed France's President Nicolas Sarkozy.

A soprano known for singing the praises of the party, Peng holds the rank of army general and starred for 24 years in an annual Lunar New Year gala broadcast on state television and watched by hundreds of millions of viewers.

Her husband, a decade her senior at 59, is set to take over next year as China's president, but when he joined the Politburo Standing Committee, the country's highest ruling body, in 2007 she was far better known.

Peng finally retired from the television show shortly afterwards -- with some speculating it was to avoid overshadowing Xi -- and has since scarcely been referred to in China's tightly controlled state-run media.

But she will bring an unprecedented splash of stardust to a position whose occupants have long been expected to remain in the background.

"As an artist she may suffer in the way that Carla Bruni has a bit," said Michel Bonnin, director of the Franco-Chinese Centre at Tsinghua University.

But Peng can help Xi "to have a less dull image than Chinese politicians usually do", Bonnin added.

The wives of China's leaders have kept low profiles since the 1970s downfall of Jiang Qing, Mao Zedong's last wife and widely-loathed member of the radical Gang of Four blamed for many of the excesses of the Cultural Revolution.

"After the Mao era, the wives of senior Chinese leaders stopped appearing in public," said Zhang Yaojie, a researcher at the National Academy of Arts.

Liu Yongqing, the wife of current President Hu Jintao, has often accompanied him on overseas trips but did not speak in public, let alone cultivate a public persona.

But Peng will be a deeply atypical first lady. In videos seen on the Internet, the 49-year-old seizes the limelight with her high cheekbones, thick jet-black hair, and a radiant smile.

Her costumes range from military uniform to richly embroidered ethnic dress, and her repertoire includes syrupy melodies and folk songs with lyrics altered to glorify the Communist Party.

Her husband is a Party "princeling" who has served in the military himself, and her version of one traditional Tibetan tune describes the People's Liberation Army (PLA) as "the saving star of the Communist Party".

In recent months she has had a behind-the-scenes role as artistic director for military troupe performances welcoming the party congress, according to the few mentions of her in state media.

Peng comes from an area in the eastern province of Shandong known for its peony flowers -- she was nicknamed the "Peony Fairy" by her admirers -- and joined the army at the age of 18.

A semi-official biography posted on Chinese web portals tells how she began as an ordinary soldier but began performing at PLA shows to boost troop morale.

In the 1980s she was one of the first people to take a master of arts in folk music in China, and her professor has spoken of her dedication to her studies.

She has since performed in 50 countries.

But in past interviews with Chinese media Peng has been keen to convey a homespun image, telling a state-controlled magazine she has simple tastes, enjoying "going to the market by bicycle and bargaining with vendors".

She has heaped praise on the "ideal husband" she married 25 years ago and with whom she has a daughter, now a student at Harvard.

"He is simple and honest, but very thoughtful," Peng told the China News Weekly.

She said he told her: "In less than 40 minutes after I met you, I knew you would be my wife."

But Peng's parents were not keen to see their daughter marry such a senior figure, fearing she would not be treated well because of her humble origins.

"He treats me like a little sister. Jinping is always busy. He is concerned about thousands of households, without thinking of himself," she was quoted saying by a government site.

"When he is at home, I cook the dishes he likes to help him relax."

Peng became a World Health Organization ambassador for the fight against AIDS and tuberculosis last year, and Bonnin suggested she could "play a Western-style first lady role", rather than just following her husband on official visits.

But Zhang was sceptical. "In China, the first lady remains a mystery," he said.