Sir Ian McKellen has revealed he has been living with prostate cancer for several years, but says he currently requires no treatment.

Speaking to the Mirror, the gay actor said: “You do gulp when you hear the news. It’s like when you go for an HIV test, you go ‘arghhh, is this the end of the road?’”

Of the cancer, Sir Ian went on to say: “I’ve had it for six or seven years. When you have got it you monitor it and you have to be careful it doesn’t spread.

“But if it is contained in the prostate it’s no big deal”.

Prostate cancer is the third biggest killer of men in Britain. If affects one in 12 men. Sir Ian stressed the importance of an early diagnosis.

“Many, many men die from it but it’s one of the cancers that is totally treatable so I have ‘waitful watching’. I am examined regularly and it’s just contained, it’s not spreading. I’ve not had any treatment.”

The actor has also praised the NHS after he was recently fitted with hearing aids and is due to have a cataract removed from his eyes.

Sir Ian is attending the London premiere of the new Hobbit film on Wednesday – the movie in which he reprises his role as Gandalf the Grey.

The 73-year-old also had some advice for people of a similar age – do some exercise, which in his case is pilates.

He said: “I recommend it to anyone of my age because the temptation is not to exercise as you get older. Well you should.”