The first court cases proved to be heavy strain on Michael. He had been taking painkillers, Valium, Xanax and Ativan to deal with the stress of the allegations. His health deteriorated to the extent that he cancelled the end of the 'Dangerous' world tour and went into rehab.

More recently in 2008, it was reported that Michael was suffering from MRSA and chest problems. But prior to his "special announcement" at O2 Arena, Michael had a series of health checks to prove that he was fit enough to perform on stage once again.