The X Factor judge says on Dannii Minogue Uncut: Piers Morgan's Life Stories - an additional show to the ITV1 programme broadcast at the weekend - that a journalist once delivered her flowers with the message 'We have tried to contact you to speak to you with no luck, and if you don't speak to us, we have it on good authority that you're HIV positive and we're running the headline.'
Dannii says on programme, aired on Tuesday: "I drove down to my doctor's office, sat there, put my arm out and said, 'I need this test done immediately,' and all I could do was have this piece of paper slapped on their desk to say, 'No I'm not HIV positive, there is no story' - and it quickly and quietly went away."
She added: "I didn't want to have to go through that, how many times does anyone have to give blood to prove some accusation? It was just weird... I don't understand why someone would do that.
"I didn't know why someone would be ... kind of on my case about something like this, I had been working for an AIDS charity, the Terence Higgins Trust, not many people want to be involved with charities like that, because they want to be involved with the cuddly, nice charities, and this is kind of heavy real life stuff."
:: Dannii Minogue Uncut: Piers Morgan's Life Stories will be shown on ITV2 on Tuesday at 9pm.