Trending: Madonna proves that shocking is in her DNA

When Madonna flashed her right breast during a concert in Istanbul last week, it was yet another feat of daring to add to her already rich back-catalogue of provocative self-promotion. The megastar, 53, has made headlines in the past for a sharing a kiss with Britney Spears and for seducing a black Jesus in the video for her 1989 song "Like A Prayer". In 1990, she was threatened with arrest by the Canadian authorities for a segment of her Blonde Ambition tour in which she appeared to masturbate on-stage. And in 1994, she published a coffee table book called Sex with the photographer Fabien Barron, which left little to the imagination.

In February, her performance at the Superbowl drew criticism when the rapper MIA, who she was singing with, made a lewd gesture live on national TV. Madonna was later quoted as describing MIA's action as "teenage" and "negative".

But that didn't seem to be a problem when she exposed herself during the first leg of her MDNA tour in Turkey, a predominantly Muslim country which, although not as strict as many in the region, is known for its relative conservatism.

During a set in which she removed her jacket and top, Madonna proceeded to unhook one cup of what looked suspiciously like a nursing bra to reveal her nipple. She then hurriedly fastened it up again – possibly having thought better of it – as the crowd roared its approval.

Her album MDNA was released in March to tepid reviews and a certain amount of po-faced scorn that a woman of her age would continue in so youthful a vein as pop music and culture. But her accompanying tour, which kicked off last week, will no doubt silence her detractors as her stage presence remains and vivacious – and volatile – as ever.