George Michael is suffering from a potentially life-threatening lung condition, it has been claimed.

The British singer was hospitalised with pneumonia while in Vienna, Austria, last week. He was forced to postpone the rest of his Symphonica world tour in order to recuperate.

Austrian media outlets are reporting that the star has developed a new lung condition. George is believed to have acute respiratory distress syndrome, known as ARDS, which stops oxygen entering the blood stream.

The 48-year-old star is thought to be using a special bed as he battles the illness. It's called a Triadyne Proventa bed, and costs around 100,000. It is used when people are having problems breathing and sees patients strapped in and then tilted to alleviate pressure on the lungs.

"With the lungs not functioning well, the heart has to pump harder to shift the blood around the body, which would make it harder to survive. This bed tries to get the lungs functioning as best they can," explained Dr. Carol Cooper, medical expert for British newspaper The Sun.

"He is in a critical condition, which means he could die. We still don't know why pneumonia affects some people more than others. But if you are middle-aged, and maybe with other problems such as with your immune system, your outlook is not so good."

George's boyfriend Fadi Fawaz spoke out over the weekend, insisting the singer is responding well to treatment.

The singer's representative hasn't commented on the new reports.

A spokesperson for the AKH hospital in Vienna has said: "As requested by the patient, there will be no further statements or updates."