The front stage contained the usual high-tech apparatus and lighting set befitting for any loud, rock concert. Except that those filling in the seats of the Summer Theatre in Dobrich on July 30 looked less like teenagers, and more like grandparents.

At 8.30pm out from the backstage, they made their appearance. Everyone began clapping as three young male musicians took up positions with their respective instruments. The intensity of the applause reached a feverish pitch when a woman in a stylish red dress made her entrance.

She waved to the audience. "I know all of you are very musical and appreciate music very much," she told them, then proceeded to sing To Be Blessed Is to Be Happy.

"Lili Ivanova has a very fine voice. A very unique voice," Emil Penchev, a 50-year-old computer engineer who has attended 12 of her previous concerts, said to The Sofia Echo.

Lili's entourage proved well adept at providing a broad range of musical backdrops and instrumental beats. For the first song, Ognyan Enev played the saxophone to the supple tune of Kenny G, best known for his 1986 hit Songbird. He then went behind the electronic keyboards, transforming it into a cocktail-lounge piano to accompany Lili's next song, Don't Die from Unhappiness. And in Be My Dream All My Life, he picked up a trumpet and produced new adult contemporary (ie, smooth jazz) rhythms.

The electrical guitarist, Bisser Ivanov, also highlighted his instrument. At times he would pluck his strings as though it were a Spanish guitar. Then, like that of Carlos Santana, and then 1960s rock. When it came to Orlin Tsvetanov, he would perform haunting, Hungarian Czardas-like melodies on his violin.

About 45 minutes into the show, at the end of each song, little children in ones, twos or threes would come on the stage and present Lili with bouquets of flowers. Twenty minutes later, it was older children. Then teenagers. And then middle-aged people. "My, they're getting bigger and bigger!" Lili remarked.

As bedtime approached, some in the audience began to feel sleepy and departed. But not Lili. Displaying no signs of weariness or drowsiness whatsoever, she and her band drove on non-stop until nearly midnight.

About half-way through the performance came a big surprise, at least for me.

"This lady sitting next to me says that she is the same age as Lili," Emil said, gesturing towards a conservatively dressed woman with a wide grin. She must have been at least 70. Only she wasn't joking.

Though rumour mills and the media have long speculated about - and come up with varying figures - concerning her exact age, experts believe that Lili Ivanova was born in 1939, in Koubrat, a town in the midst of corn and sunflower fields, far removed from Doctors' Garden in Sofia, near her current residence.

Her first profession was actually that of a nurse. Lili had studied at the Varna Medical School, and then returned to her hometown, where, in all likelihood, she would have remained for good.

But Lili had always had a knack for singing. In 1961, she successfully auditioned at the Concert Directorate in Sofia, thereby launching her music career. Much of her early breakthroughs came in Romania, where she had her first major concert tour and extensive television coverage. A Romanian record company also produced her first album, Recital in 1963.

Lili has since gone on to record more than 500 songs in 35 albums. Her popularity soared in the coming decades, the "Golden Age of Pop Music", as regarded by the young generation of the time. Some of her biggest hits include Saturday Night, Camino, Heavy Wedding, and My Mother. According to her website, in addition to Bulgarian, she can sing in English, Italian, German and Spanish (albeit not fully understanding them). Lili has also toured countries as far flung as Portugal, Cuba and Japan, and commands a loyal following in Germany and the former Soviet Union.

Besides entertainment, she has taken up philanthropic causes through the establishment of the Lili Ivanova Foundation, a charity for orphans.

But her single most talked about undertaking came about when she featured herself in the first issue of Playboy Bulgaria. It was a sellout.

"I like taking up challenges and seizing opportunities," she told journalists regarding the venture. She was reported to have been 62 at the time.

When asked about her staying power, Lili explained that it all comes down to her genes and persona. "Maybe the secret is the love that I have, which radiates around me." Her favourite foods include salads with boiled eggs, chocolate, kiwi and tiramisu. "I don't make sacrifices when it comes to living well; I eat everything - but not too much," she said in an interview with 24 Hours. With regards to liquids, she says that she abstains from alcohol, but likes fresh milk, fresh juice and a cup of hot water in the morning.

Naska Alexieva, a 43-year-old office manager, doesn't count Lili among her favourite singers, nor has she ever been to any of her 10 000-plus live performances. But she feels that she knows Lili well. "My friends and I…and just about everyone tell lots of jokes about Lili," she says with a chuckle. Rousska Geogieva (55), a custodian, says that she and her husband have had frequent arguments over music. "To me, Emil Dimitrov was the greatest singer of all time; but for him, Lili is the undisputed Queen of Pop Music."