Reality TV star David Gest appeared "frail" when he was spotted in public in the days before his death, according to reports.
The former Celebrity Big Brother contestant and ex-husband of Liza Minnelli was seen being helped on to a London Underground train and looked "pale", an onlooker told The Sun.
David, 62, was found dead at a luxury London hotel on Tuesday morning after he had reportedly not been seen for two days.
The close friend of Michael Jackson was due to tour the UK in a musical show called David Gest Is Not Dead, But Alive With Soul, named after fellow Big Brother contestant Tiffany Pollard mistakenly believed he had died in the house.
Police and paramedics were called to the suite at the Four Seasons Hotel in Canary Wharf and he was pronounced dead at the scene.
A Metropolitan Police spokesman said a post-mortem was yet to take place although his death was being treated as non-suspicious. The Four Seasons Hotel has refused to comment.
The former music manager is understood to have spent half a year living at the hotel as he prepared for his 24-date tour, due to begin in York in July.
According to reports, David had suffered from ill health in recent months and had been taking medication to treat pneumonia. In the week before his death he was photographed sitting on a Tube train after boarding at Victoria Station with help from staff on the platform.
Onlooker Matt Hare, 34, told The Sun: "I saw him on the platform. It looked like he was asking a TfL guy for instructions or assistance. The guy helped him on to the carriage and made sure he was OK. David looked frail and quite pale and was kind of just staring up at the Tube map."
The last post David shared with followers on Twitter was a photo of himself with members of the Dylan Tombides Foundation, an organisation set up in memory of the 20-year-old West Ham footballer who died in April 2014.
The post was dated April 6. His death was confirmed by friend Imad Handi, who paid tribute to the "larger than life" character.
David, who grew up in Los Angeles where he was a friend of the Jackson family, had recently spoken of his fondness for life in Britain.
He told how he had developed an affinity with the city of York and said he would "never" go back to LA in an interview with the Grimsby Telegraph.
"I will die here and want to be buried in York. I love this country much more than my own."
David became a household name in 2002 after marrying Liza in a lavish ceremony that included Michael Jackson as best man and Elizabeth Taylor as maid of honour.
The relationship lasted just 18 months and there followed an acrimonious divorce battle, although the final settlement took place outside court.