Breaking: Sam Neill's cause of death revealed by agent

New Zealand actor Sam Neill died from pneumonia, his long-time agent has confirmed.

The My Brilliant Career and Jurassic Park star died in Sydney on Monday aged 78.

Philip Grenz, Neill's agent of 19 years, confirmed the actor's cause of death in a statement released on Thursday.

"As Sam Neill’s longtime rep, I spoke with his family and wish to clarify some details for his fans," the statement said.

"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.

"As Sam was an intensely private man who loathed a fuss, his family will honour him with a private family memorial at his farm in New Zealand at a still-undetermined later date."

Neill's death was confirmed in a statement posted online earlier this week. It described his passing as "sudden and unexpected".

"Sam was surrounded by family and passed with the dignity that has characterised his whole life," the statement said.

Neill rose to fame in the 1977 film Sleeping Dogs before going on to star in My Brilliant Career, Jurassic Park, The Piano, The Dish and Possession, among other films.

In 2023 he revealed he had been diagnosed with angioimmunoblastic T-cell lymphoma, a rare type of non-Hodgkin lymphoma, in early 2022.

He entered remission later that year after a rare anti-cancer drug worked, but needed ongoing infusion treatment.

In April he announced that he was cancer-free.

The actor was also knighted in 2022, becoming Sir Sam Neill.

Tributes flowed for Neill this week, including from Prime Minister Anthony Albanese who said he had "earned a special place in Australian hearts".

"Wry and dry, thoughtful and laconic, Sam fought illness with the same dignity, humour and conviction that gave strength to his every performance," he said in a statement on X.

Heartfelt messages were also released from many within the film and television industry this week.

Filmmaker Steven Spielberg, who directed Jurassic Park, described Neill as "exceptionally collaborative".

"It was a stretch for him to play a character who acted as though children were messy and smelly because this was the opposite of the loving father he was to his children," Spielberg said.

"I adored making all the Jurassic movies with him.

"Along with Laura Dern and Jeff Goldblum, we will always have our Jurassic family, and Sam will never be forgotten by us or his many millions of fans around the world."

His Jurassic Park co-stars Laura Dern and Jeff Goldblum shared their own tributes, describing him as a "beloved lifetime friend".

Australian actress Nicole Kidman, who co-starred with Neill in 1989 film Dead Calm, said he "was one of the greats".

RNZ/ABC