Sam Neill’s cause of death was pneumonia, his longtime representative has revealed.

The 78-year-old actor’s “sudden and unexpected” death was announced on Monday, just three months after Neill revealed he was finally cancer-free since being diagnosed with stage three angioimmunoblastic T-cell lymphoma, a type of blood cancer, in 2022.

After years of chemotherapy, Neill took part in a successful clinical trial for CAR T-cell therapy, a form of cancer immunotherapy that is particularly successful in treating certain types of blood cancers.

On Thursday, Neill’s representative, Philip Grenz, said he was revealing Neill’s cause of death after speaking with the actor’s family, due to “inaccuracies and outright falsehoods” in media reporting.

“Sam passed away from pneumonia. Prior to becoming sick, Sam had valiantly fought and beaten lymphoma through a new treatment called CAR-T therapy. In addition to running his award-winning winery, Two Paddocks, Sam had filmed four projects back-to-back during the past year, all of which will be released within the coming months,” Grenz wrote in a statement.

He described Neill as “an intensely private man who loathed a fuss”, which was why his funeral will be a private memorial held at his farm in New Zealand on an undetermined date.

“I’d like to thank those who were truly close to Sam for considering his privacy with the respect he earned and his loved ones need and deserve during this immeasurably difficult time,” Grenz said.

Fans who want to honour Neill’s memory were directed to make donations to “one of the causes he cared about most deeply” instead of sending the family flowers. The causes listed were the Dunstan Hospital Foundation in Central Otago, the area where Neill lived in New Zealand; the Snowdome Foundation, a not-for-profit blood cancer foundation that Neill was campaigning with when he died to improve access to blood cancer treatments including CAR-T therapy in Australia and New Zealand; and any New Zealand charities working to protect the local environment and wildlife.

In the statement announcing Neill’s death, his family specified he had not died of cancer. Reports emerged soon after that he had been sick with pneumonia in the days before he died.

Neill’s former partner, the ABC journalist Laura Tingle, told ABC Radio Sydney on Tuesday that years of cancer treatment had exhausted him.

“The bottom line is he’s been fighting various forms of cancer for at least the last five years intensively, and that takes a toll on anybody’s body and he’d had a lot of chemo and a lot of immunotherapy and thankfully it had finally cleared him of the blood cancer that he had. But that left him pretty compromised in terms of his immune system and I think his poor body just got a bit exhausted, as makes sense,” Tingle said.

“He’s been pretty sick for the last couple of weeks and everybody who loved him has been willing him on from near and far. But I think it was just a bit too much to recover from one more time.”

Neill’s peers, friends and admirers spanning New Zealand to Hollywood have paid tribute to him since his death was announced, remembering him as a gentleman.