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Harry Potter star Alan Rickman's secret cancer battle while filming: revealed

The actor struggled during the shooting of the Harry Potter films

Harry Potter actor Alan Rickman sadly died from pancreatic cancer in 2016, and prior to his death, he was a prolific journal-keeper, regularly jotting down his thoughts.

READ: Alan Rickman didn't enjoy playing his most iconic character – Snape

In a newly released excerpt from one of his 2005 journals, the Snape actor, who was privately battling aggressive prostate cancer at the time, revealed why he agreed to keep filming the fifth installment of the franchise, despite being unwell.

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"Finally, yes to HP 5," he wrote. "The sensation is neither up nor down. The argument that wins is the one that says: 'See it through. It's your story'."

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It is believed that Alan kept his 2005 cancer diagnosis to himself, rather than sharing his ill-health with the rest of the cast, many of whom he was close to.

Other journal entries detailed his co-star Michael Gambon's illness.

Alan Rickman appeared in all of the Harry Potter films

Michael, who played Dumbledore, was struggling with memory loss and found it hard to remember his lines, with Alan writing: "He's vulnerable after his illness and yesterday's primer was no joke for him.

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"The lines are a real problem for him. Technology helps and why not? It's never great when it's just a memory loss – no relaxation, no freedom, no contact."

Alan Rickman's Snape was a favourite among Harry Potter fans

Harry Potter wasn't the only project that Alan worked on while unwell. He also started filming for Alice Through The Looking Glass, but was replaced by Bill Nighy, who spoke of Alan's bravery.

"At the time, we didn't really know how ill he was. Obviously, it was a great loss to everybody," Bill told The Guardian.

Read more of Alan's behind-the-scenes Harry Potter secrets in his journals, out October 4.

Madly, Deeply: The Alan Rickman Diaries, £20, Amazon

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