Longtime Neighbours star Ian Smith has been diagnosed with terminal lung cancer.

The 86-year-old actor, best known for playing Harold Bishop on the show, revealed the news in an interview with Channel 10 on Monday evening.

“I found out a few months back that I have cancer. That I have a very aggressive, non-fixable cancer … they expect me to die,” he said.

Footage of Smith’s farewell to his cast and crewmates on one of his last days on the Neighbours set showed the actor in tears paying tribute to the show.

“I’ve had the most privileged life … we didn’t just make a soap, we made the best bloody soap there was to make. I have met the most beautiful people,” Smith said.

Smith was diagnosed with a rare type of lung cancer called pulmonary pleomorphic carcinoma. The actor has received three rounds of an immunotherapy treatment he described as relatively new to the medical world.

“I’ve really put my hand up to be a guinea pig. Plus the fact I don’t want to die and I want to stay alive with quality for as long as I can,” he said.

“I wake up every morning hoping there’s no pain, because I know that’s the beginning of the bad part.

“I’m hoping I go the nice way.”