The American operatic baritone said: "There was a point in my career I had to straighten out my act and I thought that was the most intense moment I could go through, dealing with my own problems.

"But lo and behold I'm dealt this card and it's 10 times harder."

The influential singer-songwriter will be performing on stage with his sick mother, folk singer Kate McGarrigle, in aid of Cancer Research UK.

In 2002 Rufus sought rehabilitation, following advice from his friend Sir Elton John, for his addiction to the drug crystal meth which left him temporarily blind.

But he reckons that experience was nothing compared to the "horrific" time his family are going through since his mother was diagnosed with the rare and serious clear cell sarcoma cancer in her liver.

Rufus has called on a host of his British friends to lend their talents at the charity evening, including Boy George and Elbow's Guy Garvey.

He also reunited comedy double-act French and Saunders after the pair called an end to their 30 year stage partnership with a final performance at London's Theatre Royal last November.

The A Not So Silent Night concert at the Royal Albert Hall for Cancer Research UK and the Kate McGarrigle Fund takes place on December 9.