George Michael has reportedly been rushed to hospital.
The 50-year-old singer is said to have fallen ill last week and collapsed in his Highgate home in North London.
A spokesperson for the London Ambulance Service told the British newspaper The Mirror two units were sent to George's neighbourhood last Thursday after a friend called emergency services for help.
"We were called just before 8am on May 22. We sent two ambulance crews and staff treated one patient, a man, who was then taken to hospital," the representative stated.
Witnesses told the publication emergency services left the home with George around noon, four hours after they arrived at his house.
George's agent has refused to comment on whether the musician has been released from medical care and has not said if drugs were involved.
"George Michael was in hospital for routine tests but there is nothing further to say," his representative said.
George drove his car into a storefront in July 2010 and later served four weeks in prison for his DUI.
The singer has also experienced a number of harrowing near-death events, including being unconscious for three weeks in December 2011 after developing pneumonia.
In May 2013 George fell out of his moving vehicle while driving on a motorway in the UK.