Taking to social media the day before the last two episodes aired, Mr Clarkson said he had some 'sombre news'.
He continued: "We try to keep the show charming and cheerful, but the final two episodes are none of those things really.
"They're a really difficult watch."
Prostate cancer
He is seen revealing a prostate cancer diagnosis to Charlie Ireland and Kaleb Cooper, describing it as 'aggressive' but in the early stages.
The 66 year old said he has known since May.
FARM HEALTH: Nip It In The Bud campaign helps diagnose former farmer with prostate cancer
Clarkson's Farm season five
The latest series of Clarkson's Farm has already documented Mr Clarkson's health issues, after a stint in hospital with a suspected heart attack.
The final episodes show Mr Clarkson in hospital.
Clarkson's Farm star Kaleb Cooper says farmers must talk about mental health
He said: "Some of the treatment has gone awry.
"I'm going to be here for a little while. I don't know what's going to happen."
- If you need support you can reach out to various farming charities including the Farming Community Network
