Pop star, icon, and Kabbala aficionado Madonna turns 50

Madonna won't have much time to fret about turning 50. While many people passing the milestone may prefer to pause and reflect, the "queen of pop" is in the midst of final preparations for her world tour which kicks off in Cardiff, Wales next Saturday, a week after her birthday.

If previous shows are anything to go by, the 40-plus "Sticky & Sweet" dates around the globe will put Madonna under the kind of physical and mental strain that would test a woman half her age.

But the world's most successful female recording artist has never let age, sex or background get in her way, and has remained in the ascendancy with an uncanny ability to reinvent herself just when the old Madonna was nearing her sell-by date.

Her latest reincarnation is a shrewd businesswoman, after she severed ties with long-term record label Warner Brothers to sign up with Live Nation, a company that until recently specialized in music tours.

As well as earning a reported $120 million over the life of the agreement, Madonna appeared to be among the first to recognize which way the music industry was heading.

Recorded music, many artists now believe, is making them less money than live performing, meaning they are looking to spend less time in the recording studio and more on the stage.

The last few years have not all been easy for Madonna, however.

A celebrity who often bristles in the media glare, Madonna may be universally admired but she is not universally loved.

Her decision in 2006 to adopt a young Malawian boy whose mother died was controversial both in the southern African country and further afield.

Aid groups in Malawi said the authorities had bent the rules to accommodate the super-star, and the adoption was challenged in court. Not for the first time, Madonna prevailed and the adoption went through.

Madonna has two other children - son Rocco with her husband the British film director Guy Ritchie, and daughter Lourdes from a previous relationship.

She directed her first feature film that came out in 2008, and although reviews were mixed, there were harsh words for a woman some feel should forget about movies and stick to music.

Her eight-year marriage to Ritchie has also come under increasing scrutiny after tabloid newspapers in Britain, where she spends much of her time, have reported that the couple are planning to divorce.

Both Ritchie and Madonna have denied the reports.