According to reports, the reality star was left with just £57,000 in his bank after becoming a regular at the casino
According to The Sun, his company David Gest Limited equated debts of £474,000 after he became addicted to gambling in his final months.
The newspaper also reports that he was left with just £57,629 in the bank after blowing his cash on 50p-a-time slot machines in casinos around the UK.
In an effort to break even, David was apparently prepared to sell some of the sought-after memorabilia that he owned.
Read more: Kym Marsh pays tribute to her 'wonderful friend' David Gest
A spokesperson for David said they were unaware if the mountain of debt existed.
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The rep said: "David enjoyed gambling and was a popular figure at casinos around the world. He loved to tell stories of his casino triumphs.
Read more: David Gest was 'strung out on sleeping pills' before death
"As far as we are aware, David has left no gambling debts anywhere. To suggest otherwise would be a deeply sad attack on a very popular man."
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David would reportedly feed two slot machines at the same time - stopping only to take selfies with fans.
A friend told The Sun: "He would spend 24 hours a day chasing the jackpot. David wouldn't think twice about spending £10,000 in one sitting.
"His losses didn't seem to affect him but in a 12-month period it was a substantial amount, it was six figures."
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Someone who spotted him gambling shared on Twitter: "I once saw David Gest in a casino playing two slot machines at once. Respect that level of degeneracy."
While another friend told the tabloid: "David loved giving off the image of being successful. He worked hard to keep up that image and sometimes the money wasn't coming in."
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Read more: David Gest appeared 'frail and pale' before his death
David was sadly found dead at the luxury Four Seasons hotel in London on Tuesday.
Staff hadn't seen the star for 48 hours before his body was discovered