• David Bowie told friends he was suffering from liver cancer in late 2014
• He knew illness would kill him a year before he passed away on Monday, according to theatre director Ivo van Hove
• Collaborator describes how he continued working and even said "Let's make a second one now" just weeks ago
• His last album Blackstar features lyrics: "Look up here, I'm in heaven"
David Bowie knew he had terminal liver cancer more than a year ago but was desperate to live so he could see his daughter grow up, according to one of his closest collaborators.
The star battled illness for 18 months before his death on Sunday, but kept it a secret from all but close friends and family - even though he knew it was likely to kill him.
Despite his cancer diagnosis, Bowie continued to make music, releasing his final album Blackstar just two days before he passed away in New York on Monday, surrounded by his family.
During his illness he was sometimes too frail to work, but weeks before his death he told the director of a musical based on his songs that he wanted to "make a second one now" in a sign that his creative spirit was undiminished.
Ivo van Hove told Dutch radio station NOS.nl: "He told me more than one year and three months ago that he had liver cancer, just after he had been told himself. He said that because he knew that he may not always be able to be around."
In his dying days, Bowie dispatched poignant thank-you notes to friends who remained unaware he was at death's door until yesterday's announcement.
The last time he was seen in public was at the premiere of musical Lazarus, based on his back catalogue, when according to Mr van Hove he was so ill that he "collapsed from exhaustion".
The director was sworn to secrecy about Bowie's cancer battle, but the star told him: "We have to work together very intensely for the next year and I want you to know, if I cannot be there, why that is."
During rehearsals for the musical the singer was "very fragile - physically, not mentally", according to the director, but he refused to stop working and "fought like a lion" through his illness.
Mr van Hove said that at the premiere in New York on December 7, Bowie tried to contain his emotions despite coming to the end of his battle with cancer.
"It was written that he looked so well, so healthy," Mr van Hove said. "But behind the podium he collapsed from exhaustion. It was then that I realised it may be the last time I would see him."
Talking to The Times, he added: "He was really weak and when we came off stage he had to take a seat." Then he said, "Let's make a second one now," so he still had mental energy to go on.
"I could see the tears behind his eyes, because he was not a man to show off his emotions. He was really in deep fear.
"I felt he was not in a death struggle but a struggle for life - he wanted to live on. He has a daughter of 15 and he really wanted to go on, but it was physically not possible."
Bowie is survived by his wife Iman, his 44-year-old son Duncan Jones, a Hollywood film director, and his teenage daughter Alexandria.
Producer Tony Visconti, who worked with the star on most of his albums, said he had known for a year that Bowie was dying.
He suggested that Blackstar, Bowie's 25th studio album, was made as a "parting gift" to the world by a man who knew that he did not have much time left.
The musician's biographer claimed yesterday that he had suffered six heart attacks in recent years after largely disappearing from the public eye more than a decade ago.
Wendy Leigh, told BBC News: "He didn't just battle cancer... he had six heart attacks in recent years. I got this from somebody very close to him."
But friends suggested that Bowie was determined to keep his privacy as "the greatest luxury" and "slip away almost like a phantom", according to the Guardian.
Figures from the music industry said they had heard rumours that he was gravely ill, but the seriousness of his condition was not widely known before his death.
Musician and producer Brian Eno, who collaborated with Bowie on three albums, said he had received an email from the singer a week ago ending with the words: "Thank you for our good times, Brian, they will never rot."
Eno said: "I realise now it was his way of saying goodbye."
Bowie's passing came just three days after the release of a music video which featured chilling footage of the singer confined to a hospital bed with his eyes covered by a bandage as he sang: "Look up here, I'm in heaven."
Few were aware how the reclusive singer's hedonistic rock and roll lifestyle had caught up with him after years of chain-smoking and cocaine abuse.
In 2014, the year his cancer was diagnosed, the Brixton-born star flew his teenage daughter - known as Lexi - and his wife from their Manhattan home to Britain to visit his childhood haunts.
They took photos outside the suburban semi in Beckenham, Southeast London, where Bowie grew up, and visited tourist attractions such as the London Eye without being recognised.
Bowie's devastated wife of 24 years, Iman, 60, shared her heartbreak online with apparent references to her husband's death on her Instagram page over the weekend.
She posted the messages: "The struggle is real, but so is God", and: "Sometimes you will never know the true value of a moment until it becomes a memory."
News of Bowie's death was confirmed by his son Duncan, who tweeted a touching photo of himself as a baby with his father and wrote: "Very sorry and sad to say it's true. I'll be offline for a while. Love to all."
A spokesman for the singer said: "David Bowie died peacefully surrounded by his family after a courageous 18-month battle with cancer.
"While many of you will share in this loss, we ask that you respect the family's privacy during their time of grief."
Bowie's first wife Angie, who is appearing on Celebrity Big Brother, was informed off-camera of her ex-husband's death and decided to continue her stint on the Channel 5 reality show.
Bowie shrines popped up around the world, with many fans in tears as they laid flowers.
Celebrities and public figures rushed to pay tribute to the artist regarded as one of the most radical and ground-breaking musicians of the past 50 years, whose Ziggy Stardust persona helped usher in the glam rock era but who also explored disco and electronic music as well as acting in several films.
Sir Paul McCartney said: "Very sad news to wake up to on this raining morning. David was a great star and I treasure the moments we had together."
One of the more unusual tributes came from Cardinal Gianfranco Ravasi, the Vatican's culture chief. He quoted Bowie's first hit, Space Oddity, which includes the line "may God's love be with you".
Glastonbury founder Michael Eavis said of the singer, who played the Somerset festival twice, in 1971 and 2000: "He's one of the three greatest in the world ever - Frank Sinatra, Elvis Presley and David Bowie. There's no one else even close."
- Daily Mail