Willie Nelson was yesterday forced to cancel a fundraising gig in Denver after he was admitted to hospital with "breathing problems". 

The singer, who has released over 200 albums and has won seven Grammy Awards during his lengthy career, was scheduled to play at a charity event for the Dumb Friends League in Colorado.

A representative for the event revealed that the 79-year-old was "suffering from breathing problems due to the high altitude and emphysema", but no further information about Nelson's condition has yet been revealed. 

The singer recently insisted that legalising marijuana would save "a whole lotta" lives and money.

Asked whether the drug should be legalised, he replied: "It has to, because economically we need the money – why give it to criminals? Most people realise it's not a deadly drug like cocaine or cigarettes."

Nelson was arrested in 2010 for marijuana possession.