Madonna has sparked a storm of controversy online by promoting her upcoming album Rebel Heart with iconic images of the likes of Martin Luther King, Jr. and Nelson Mandela bound with black wire.

After posting the album cover art, which appears to show Madonna tied up, the provocative pop superstar offered up photoshopped shots of King, Jr., Mandela and Bob Marley with the same ties cutting into their faces.

Accompanying the Mandela shot, Madonna wrote, "This #rebelheart fought for freedom!" and added, "This #rebelheart had a dream!" alongside the photo of Dr. King, and, "This #rebelheart sang about One Love!" in the caption for the Marley snap.

Critics were quick to attack the singer with one tweeting, "To lessen Mandela's and Dr. King's achievements as far as making their faces involuntarily a part of a marketing campaign for some irrelevant pop music is just a huge perception disorder... I'm already unnerved by all this pictures with strings in people's faces."

And a former Madonna devotee added, "Officially lost a fan in me..."

Madonna was forced to release six tracks from her new album last month (20Dec14) following an Internet leak. The entire album was then posted on various sites in the run up to Christmas Day (25Dec14).