McKellen said he initially feared the worst upon getting the diagnosis.
"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 come and say you have cancer of the prostate and then they say you can have it zapped, you can have it snipped but you are not a candidate for that. You are waitful watching.
"I have heard of people dying from prostate cancer, and they are the unlucky ones, the people who didn't know they had got it and it went on the rampage. But at my age if it is diagnosed it's not life threatening."
In the wake of the widely circulated news, McKellen's agent, Chris Andrews, later caused confusion when he denied that the star has been battling cancer.
"No, he does not have prostate cancer," Andrews was quoted as telling ABCNews.com. "That was taken out of context and from an interview from years ago."
Curiously, the website's report added that "Andrews pointed to McKellen's appearance at the premiere of The Hobbit: An Unexpected Journey in New Zealand on November 28 as evidence of the actor's health."
McKellen, as we know, did not attend the premiere in Wellington.
ABCNews.com's report also claimed that CLD Communications, which represents McKellen in the UK, had confirmed that the Mirror's story "was taken out of context."
McKellen has since set the record straight.
"There have been new reports in the press of the old news that I have early prostate cancer," McKellen wrote in a post on his official blog. "This was diagnosed six or seven years ago.
"There is no cause for alarm. I am examined regularly and the cancer is contained. I've not needed any treatment."
All the very best to you, McKellen!
FAST GOSSIP
And finally...
* And the 2013 Golden Globe nominees are...
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* Watch: Amanda Seyfried admits she's "pretty drunk" during David Letterman appearance.
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- Rumour Has It