The 53-year-old was performing her track Human Nature in Istanbul, Turkey, when she started taking off her clothes.
But after ditching her shirt, she caught the crowds by surprise when she went on to peel down her lacy bra, revealing her nipple to the audience.
And the pop legend soon re-thought her decision, pulling an odd face as she covered up again.
Perhaps fans shouldn't have been surprised - as she did warn them, writing No Fear on her back.
Her actions may have been offensive to some members of her audience, as Turkey is a traditionally Islamic country, with a largely Muslim population.
The singer's worldwide MDNA tour kicked off in Israel last week, and will come to in England, Scotland and Ireland in July.