Prince Harry has passionately pleaded for people who may have HIV/Aids to get tested as he continued his bid to reignite awareness of the virus.
He revealed his main aim was to "reduce stigma" as he chatted with research experts and frontline staff at Kings College Hospital in south London.
The Prince said: "Something needs to change. Some people need to be reminded that this is very much - especially in London now that the numbers are going up - this is very much an issue that a lot of people look at.
"I'm not trying to scare people but ... they have a responsibility - with a relationship or with people that you love - that actually you owe it to yourself and you owe it to them just to get tested.
"It is such a simple thing to do," he added.
He asked how many people living with HIV/Aids had not told their partner about their diagnosis, to which the hospital staff collectively replied "Loads."
Staff added that there was a very small risk of the virus being passed on once treatment was under way.
Harry also asked what, if he was an "average Joe, member of the public", he should do if he wanted to get tested.
The group told him people should search SH24 - Sexual Health 24 Hours - on Google.
In August the hospital will be rolling out HIV testing to all patients, who will be able to opt out, in an attempt to normalise it.
The Prince was shown a "Keep calm and test for HIV" badge and joked: "There's nothing that 'Keep Calm' doesn't work for", prompting laughter from the room.
Continuing, he said that, in the hierarchy of medical tests, it should be "not at the top, not at the bottom, just in the middle", gesturing with his hands to indicate how the practice could be integrated.
Harry follows in his mother's footsteps by continuing to pledge his time to raise the issue of HIV/ Aids.
Diana, Princess of Wales, was the first member of the Royal Family to have contact with a person suffering from HIV/Aids.
In the late 1980s, when many still believed the disease could be contracted through casual contact, she sat on the sickbed of a man with Aids and held his hand.
Arriving at the hospital on Thursday morning, Harry shook hands with the chief executive of King's College Hospital, Nick Moberly, before sitting down to a round-table discussion about the virus.
He was told there were about 108,000 people living with HIV in the UK, the majority of whom - 81,000 - are receiving care.
Around 24% of the total are undiagnosed, which is the UK's "biggest challenge", the Prince heard.
He was then told that there are around 6,000 diagnoses per year in the UK - with nearly half of those - 2,500 - in London.
Harry also asked the experts for their views on PrEP - a drug available in America which can prevent people at risk from developing the virus.
It is not currently licensed for use in the UK, but where it is used it "significantly reduces the risk of transmission" and is "extremely cost-effective", he was told.