"Jurassic Park" star Sam Neill died of pneumonia, his agent said Thursday, in a message aimed at providing clarity to fans.

Neill died in Australia on Monday at the age of 78, his family said in a statement.

He was cancer-free at the time, his family added without elaborating on the cause of death. 

"I spoke with his family and wish to clarify some details for his fans," long-time agent Philip Grenz said in a statement to public broadcaster Radio New Zealand.

"Sam passed away from pneumonia. Prior to becoming sick, Sam had valiantly fought and beaten lymphoma through a new treatment called CAR-T therapy."

The actor's family is to hold a private ceremony in New Zealand, the agent said.

"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."

Grenz said Neill had filmed four projects in the past year, which would all be released in the "coming months", without giving further details.

Neill revealed in a 2023 memoir he was "possibly dying" with stage-three non-Hodgkin lymphoma.

But he declared himself cancer-free earlier this year, thanks to a genetic therapy that modified his immune system.

Born in Northern Ireland in 1947, he moved to the rugged South Island of New Zealand as a child.

He was christened Nigel John Dermot but decided his first name was too "effete" for New Zealand and switched it to Sam.

Neill started acting in New Zealand films in the early 1970s before moving into larger roles in Australia. 

His big breakthrough came in 1993 when he played Dr Alan Grant in the blockbuster "Jurassic Park".

When he was not acting, Neill also ran vineyards in the picturesque Central Otago region of New Zealand's South Island.

Tributes have poured in from friends, colleagues, neighbours in Central Otago, and some of Hollywood's biggest names, including director Steven Spielberg and fellow "Jurassic Park" actors Laura Dern and Jeff Goldblum.