Madonna in Madiba legal wrangle

The Nelson Mandela Foundation is to contact Madonna's lawyers after the pop star made waves by posting doctored pictures of Mandela, Bob Marley and Martin Luther King on Instagram to promote her new album, Rebel Heart.

The images were altered to show rope across their faces.

Madonna has been accused of racism on social media. But she said she was showing her admiration for the "rebel hearts".

The foundation's director of communication and outreach, Danielle Melville, said: "The foundation has not been formally consulted with regard to the use of Madiba's image .... we need to consult Madonna's team and investigate the facts."

Madiba's images are trademarked and cannot be used commercially without the foundation's authorisation.