George Michael has suffered a series of medical problems since 2011.
The singer, 50, has been out of the spotlight since last year, when he fell out of a car on the M1 motorway and was airlifted to hospital with a head injury.
In 2011 he suffered severe pneumonia which left him temporarily in a coma and meant he needed to undergo a tracheotomy in order to breathe.
He has also battled depression and drug addiction.
More top news
Nicolas Sarkozy would give Britain the chance to reverse the Brexit vote if he is elected president of France.
Wet and windy in the north tomorrow, bright and warm in the south.
The Democratic presidential told reporters: 'Anybody who complains about the microphone is not having a good night.'