"Rebel Heart" is likely a co-production with superstar DJ/producer Avicii, who Madonna worked with earlier in the year on new music. (Madonna posted an image of her with Avicii in a recording studio, using the hash tag #RebelHeart.) Both songs could be unfinished, or demo versions.
Madonna's publicist had no comment about the initial leak, though the diva's manager, Guy Oseary, Tweeted: "I would be grateful to any Madonna fans that can assist us in finding those responsible for the leak. We appreciate your help."
Madonna has been working on new music throughout 2014, often updating her Instagram feed with photos and messages regarding her progress. A new album from the entertainer is expected in 2015. It will be her first studio effort since 2012's MDNA, which debuted at No. 1 on the Billboard 200 chart.