Sam Neill has revealed his battle with blood cancer.

The iconic Kiwi actor opened up about his stage-three cancer diagnosis in a memoir that is being released next week.

He is now cancer-free but spoke candidly about his journey in his book.

In chapter one of Did I Ever Tell You This? the 75-year-old writes: “The thing is, I’m crook. Possibly dying“ and goes on to detail his angioimmunoblastic T-cell lymphoma diagnosis.

Neill started writing the memoir while undergoing chemotherapy last year.

“I found myself with nothing to do,” Neill told the Guardian.

“And I’m used to working. I love working. I love going to work. I love being with people every day and enjoying human company and friendship and all these things.

“And suddenly I was deprived of that. And I thought, ‘what am I going to do?’”

He said he “never had any intention to write a book” but once he started penning his thoughts, he just “kept on writing”.

“I realised it was actually sort of giving me a reason to live and I would go to bed thinking, ‘I’ll write about that tomorrow … that will entertain me’,” he explained to the Guardian.

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“And so it was a lifesaver really, because I couldn’t have gone through that with nothing to do, you know.”

It's more than 30 years since Sam Neill first played Dr Alan Grant in Jurassic Park. Photo / Supplied

Neill was adamant the book was not a cancer memoir, saying his condition is more of a “spiral thread” through his narrative.

He told the Guardian he experienced swollen glands during publicity for Jurassic World Dominion in March last year.

Soon after, he was diagnosed and underwent chemotherapy.

However, that started to fail and he chose to start taking a new chemotherapy drug which he will now receive monthly for the rest of his life.

He said: “I can’t pretend that the last year hasn’t had its dark moments.”

“But those dark moments throw the light into sharp relief, you know, and have made me grateful for every day and immensely grateful for all my friends.

“Just pleased to be alive.”

Sam Neill was awarded a knighthood in recognition of his "outstanding contribution to film" last year. Photo / Facebook

The interview with the Guardian took place at Neill’s Central Otago property.

“I’m not afraid to die but it would annoy me,” he said.

“Because I’d really like another decade or two, you know? We’ve built all these lovely terraces, we’ve got these olive trees and cypresses, and I want to be around to see it all mature. And I’ve got my lovely little grandchildren. I want to see them get big.

“But as for the dying? I couldn’t care less.”

He also discussed his life in the South Island.

“I have a number of friends who are real celebrities, you’d know who they are, and I wouldn’t swap my life for theirs for a moment, even though they’re immensely rich and, you know, immensely famous,” he explained.

“There’s a complete lack of privacy for one thing, and privacy is very, very, very important, I can walk down the street in Surry Hills (in Sydney where he owns another property) and get my coffee, and nobody bothers me, you know? And there’s no paparazzi. My life is my own.”