LONDON — The key to Madonna’s enduring appeal has been to stay one step ahead of the game in the famously fickle world of pop.

But a successful musical career does not always equal harmony at home, and the performer announced on Wednesday that she and British film director Guy Ritchie were divorcing eight years after their fairytale wedding in Scotland.

Madonna was married once before to actor Sean Penn in the 1980s.

Few expect the latest personal setback to get in the way of Madonna’s stellar career for long. On Wednesday and Thursday she is due to perform gigs in Boston on her "Sticky & Sweet" world tour, before moving on to Canada.

At 50, fans say Madonna is moving and shaking like someone half her age, testament to the rigorous training that underlines the drive and professionalism of a woman who rose from the humble surroundings of a small town in the US state of Michigan to international fame and fabulous riches.

But it is not just stamina and determination that have got the singer to where she is today. Perhaps more than anything else it is her ability to reinvent herself.

From the raunchy videos condemned by the Vatican to "Mamma-Donna" the mother of two heading up the aisle in 2000, she has had more image make-overs than David Bowie – and always stayed one step ahead of her detractors.

Only last year she was shaking up the music industry again, leaving her long-time record label Warner and joining concert promotion company Live Nation in a long-term deal reported to be worth $120 million.

Having earned tens of millions of dollars on the road already, she was among the first major musical acts to react to the fact that touring was making more money than recording.

After a quarter of a century at the summit of pop, she and Ritchie, 40, have amassed a fortune estimated at $525 million, of which the vast majority comes from Madonna.

Ritchie’s film making career has been a rollercoaster ride, starting promisingly with crime caper "Lock, Stock and Two Smoking Barrels" in 1998 followed by another acclaimed picture "Snatch" two years later.

But after that he struggled, directing his wife in the critically mauled "Swept Away" in 2002 before making the commercial flop "Revolver."

The studios have put their faith in his ability, though, and he is aiming for a major comeback with "Sherlock Holmes," a big-budget adaptation of the Arthur Conan Doyle stories starring Robert Downey Jr. as the Victorian-era super sleuth.

True to her reputation as a career chameleon, Madonna has also tried her hand at movies. Although her turn in "Swept Away" was treated with derision, she did win a Golden Globe award in 1996 for the musical film "Evita."

It was not surprising that Madonna begged director Alan Parker to give her the title role in a film which depicted the life of Argentine heroine Eva Peron. In many ways, Peron’s rise from poverty to president’s wife was a mirror image of the pop singer. Both clawed their way to fame from obscurity.

Madonna has also worked behind the camera, directing her first feature, "Filth and Wisdom," which received mixed reviews.

Madonna Louise Veronica Ciccone was born in Bay City, Michigan on August 16, 1958.

She was the third child born into a large, devout Italian-Catholic family. Her mother died when she was six. Her strict disciplinarian father brought them up single-handedly.