Sydney, Australia - Actor Sam Neill battled pneumonia before his unexpected death aged 78, a former co-star said Tuesday as some of Hollywood's biggest names mourned the Jurassic Park leading man.

Neill died in Australia on Monday, his family said in a statement that described the loss as "sudden and unexpected."

The New Zealander had undergone treatment for lymphoma in recent years but was cancer free, his family added without elaborating on the cause of his death.

New Zealand actor Rima Te Wiata, who starred opposite Neill in the widely acclaimed local comedy Hunt for the Wilderpeople, said her friend was not scared of dying but he would be "annoyed."

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"It really sucks, actually," she told the New Zealand Herald.

"I think he would be like: 'For goodness sake, I got over my cancer. And now look, now I get pneumonia. What next?'"

Te Wiata did not offer any more detail, and it was unclear how recently Neill may have been sick with pneumonia.

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.

Director Steven Spielberg led Hollywood's tributes to Neill, who endeared himself to fans with a modest style that belied his fame.

"I adored making all the 'Jurassic' movies with him," said the Jurassic Park filmmaker.

"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."

Jurassic Park co-star Laura Dern said Neill was a "true and noble gentleman," while Jeff Goldblum said Neill's "next great adventure begins."

Nicole Kidman, who acted alongside Neill in Australian thriller Dead Calm, said "Sam was one of the greats."

And Cillian Murphy, who worked with Neill on Peaky Blinders, said he "admired him and adored him in equal measure."

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"He was one of the kindest, funniest and gentlest people, and one of the finest actors... RIP."

Neill was born in Northern Ireland in 1947 but moved to the rugged South Island of New Zealand as a child. He was christened "Nigel John Dermot" but ditched the name in favor of "Sam" because he feared it was too "effete" for New Zealand.

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

His breakthrough came in 1993 when he played Dr. Alan Grant in blockbuster Jurassic Park, which for a period was the highest-grossing film ever made.

At one point he was even touted to replace Roger Moore in the iconic James Bond franchise.

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