Ian McKellen has been battling prostate cancer for "six or seven years".
The 73-year-old star often fears it "could be the end of the road" when he goes for a HIV test, but he now lives happily with the potentially life-threatening disease.
He 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?’ They say you have cancer of the prostate and then that you can have it zapped.
“You can have it snipped but you are not a candidate for that. You are waitful watching.”
The 'Hobbit: An Unexpected Journey' actor – who portrays Gandalf the Grey in the film series – revealed his is yet to receive any treatment for prostate cancer and insists it is "no big deal".
He explained: “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.
“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.”
Despite also suffering from a cataract and hearing problems, Ian – who realised there was something wrong when he kept going to the toilet in the middle of the night – insists he is "absolutely fine" even though doctors are "concerned" about the cancer spreading.
He added to the Daily Mirror newspaper: “You are told what the situation is: you can have an operation but there is no point me having an operation because there is no need for it.
“They are concerned about the cancer spreading outside the prostate. If it doesn’t you are fine. How do you know if it is spreading? You keep being tested.
“I just got hearing aids, I am going to have a cataract removed from my eyes, I am having an implant in my mouth, I am dealing with the prostate … I am absolutely fine thank you very much!"