The manager of Madonna has asked fans to stay vigilant after a demo of one of her new songs leaked online.

The singer has been busy working for a number of months on new material and one of her lead tracks is reportedly called 'Rebel Heart'.

A clip of a demo version of the song has found its way online and her manager Guy Oseary took to Twitter today (November 28) to ask fans to help them track the leak's protagonist.

He said: "I would be grateful to any @madonna fans that can assist us in finding those responsible for the leak...We appreciate your help..."

The leaked version meanwhile features the lyrics: "I spent some time as a narcissist/Hearing the others say, 'Look at you, look at you!'/Trying to be so provocative/I said, 'Oh yeah, that was me'/All the things I did just to be seen."

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