The family of Robin Gibb have maintained their bedside vigil as the cancer-stricken Bee Gees star lay comatose in hospital.
Wife Dwina smiled and son Robin-John waved to photographers as they entered the central London hospital around 1.30pm on Sunday.
Fans from all over the world left hundreds of messages of support and wishes for the star's swift recuperation on his Facebook page.
Emily Harrison, from Nova Scotia, Canada, wrote: "Get well, Robin, we don't want to lose another Bee Gee!! All your fans are thinking positive thoughts. May God bless you & all your families.''
Narcisse Lacroix, from the Czech Republic, described how Mr Gibb's voice was one of the first she was permitted to hear as the strict ban on Western music was eased in the former socialist state.
She wrote: ''[The] first time I heard your voice when I was 11 years old, it seems to be so long ago [sic]. In that time our broadcasters started to play western music and I learned my first English words with listening to `Sinking Ships', `I Started a Joke' and `Holiday' with a dictionary in my hand.
"I had and I still have a lot of other beloved interpreters of music and loves in real life but you are a love that lasted, some kind of a soul-mate and you always will be. I pray for you.''
Robin-John, 29, had been due to premier a collaborative classical work, The Titanic Requiem, with his father last week, but the event went ahead without Gibb due to his poor health.
Other family members, including brother Barry, 65, daughter Melissa, 37, and son Spencer, 39, had also reported to have visited Gibb, who is suffering from colon and liver cancer and pneumonia.
Gibb had surgery on his bowel 18 months ago for an unrelated condition, but a tumour was discovered and he was diagnosed with cancer of the colon and, subsequently, of the liver.
It had been thought his cancer was in remission as early as last month, but the latest deterioration in his health coincides with reports of a secondary tumour.
A statement on the singer's website RobinGibb.com said: "Sadly the reports are true that Robin has contracted pneumonia and is in a coma. We are all hoping and praying that he will pull through.
"Because of this situation, Robin's website is temporarily unavailable. Sorry for any inconvenience.''
Gibb's agent declined to comment on reports that the star may have only days left to live.
Gibb's twin brother and bandmate Maurice died from the same bowel condition that initially led doctors to operate on Robin.
Gibb's younger brother Andy, who was not part of the Bee Gees but a successful singer in his own right, died in 1988 from heart failure at 30.
Robin Gibb has enjoyed a musical career spanning six decades, from humble beginnings as part of a sibling trio in 1950s Manchester to his most recent classical venture, a requiem for The Titanic.
In the interim, he sang some of the 1960s and 1970s greatest hits, including Massachusetts, I've Gotta Get A Message To You, Lonely Days, How Can You Mend A Broken Heart, How Deep Is Your Love and Stayin' Alive.
Gibb last performed on stage in February, supporting injured servicemen and women at the Coming Home charity concert held at the London Palladium.
Gibb's band the Bee Gees will be best remembered for their contribution to the soundtrack of 1977 film Saturday Night Fever, which turned disco music into a worldwide phenomenon and placed the distinctive look of the era's hairstyles and outfits into pop culture legend.