Bee Gees co-founder Robin Gibb is in a coma after developing pneumonia. Sources say Gibb is "very ill and his family is keeping vigil at his bedside in a London hospital."

Gibb has been plagued by health problems: on March 26, he had emergency surgery to deal with a blood clot. That was the result of an earlier operation to repair a twisted intestine. And all of that was separate from Gibb's bout with colon cancer, which spread to his liver but is reportedly in remission.

Gibb's spokesman has declined to comment on the singer's health.

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