David Bowie only found out that his cancer was terminal just three months before his death on 10 January last year.
The musician, who died days after his 69th birthday, was recording his last track Lazarus when doctors told him that his treatment wasn't working, reports the Guardian.
Johan Renck who directed the video for Lazarus, said the song wasn't about Bowie dying as many assumed, because at that point he didn't know his cancer wasn't treatable.
"I immediately said 'the song is called Lazarus, you should be in the bed'," says Renck. "To me it had to do with the biblical aspect of it ... it had nothing to do with him being ill.
"I found out later that, the week we were shooting, it was when he was told it was over, they were ending treatments and that his illness had won."
In July 2015, Bowie was still determined to beat the disease. Lazarus musical director Ivo Van Hove recalls the opening night of the show: "He got through the night. I really am convinced that he was fighting death and he wanted to continue and continue. Afterwards we were sitting behind stage and he said 'let's start a second one now, the sequel to Lazarus'."
The pair were talking in BBC2 documentary, David Bowie: The Last Five Years, which airs on Saturday 7 January at 9.00pm. Made by Francis Whateley, the programme also seeks to explain why Bowie decided to keep his ill-health private.
"I don't find it strange he kept his illness so private," said Whately. "He'd had his life picked over for 40 years and he thought he had said everything he wanted to say, there was nothing more."
