Madonna has denied claims that she was racist to post Instagram photos of civil rights activist Martin Luther King and former South African leader Nelson Mandela that were altered to look like her own image on her new album.

The cover for the Material Girl's album Rebel Heart is a close-up of her face with black string on it. But her social media posts showing the faces of Dr King and Mr Mandela doctored to make it appear as though they have similar string on their faces sparked criticism from some who said they were offensive.

In a statement, Madonna said she was not comparing herself to them but acknowledging that they were rebels. She also said the images were fan-generated and denied racism, adding she also posted other famous faces who were not black.