A spokesman for the 62-year-old, who has been battling cancer and recently contracted pneumonia, was not immediately available to comment on the reports.

"Our prayers are with Robin," an unnamed family friend told the Sun newspaper, which first reported the news.

"He has kept so positive and always believed he could beat this. Sadly, it looks like he has developed pneumonia, which is very bad in his situation."

The tabloid said that Gibb's wife Dwina, sons Spencer and Robin-John, daughter Melissa and brother Barry were keeping a bedside vigil.

In February, Gibb announced he had made a "spectacular" recovery from cancer. But in late March he underwent further surgery on his intestines.

He was forced to cancel all engagements, including the world premiere earlier this month of his first classical work, co-written with Robin-John, called "The Titanic Requiem".

Gibb had emergency surgery in 2010 to treat a blocked bowel and further surgery for a twisted bowel - the condition that killed his twin brother Maurice in 2003 at the age of 53.

He was diagnosed with colon cancer, which later spread to his liver.

Gibb originally formed the Bee Gees in Australia with brothers Barry and Maurice. The group released its first record in 1963.

But it was in the 1970s that they rose to worldwide fame, producing a string of disco favorites including "Jive Talkin'", "How Deep Is Your Love" and "Night Fever".

The brothers never matched that success in subsequent decades, however, but wrote and produced a string of hits for other artists.

The band's distinctive tight harmonies and falsetto vibrato delivery helped the Gibbs sell an estimated 200 million records worldwide.

(Reporting by Mike Collett-White; Editing by Andrew Osborn)

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