Prince Harry teased superstar singer Rihanna that taking an HIV test with him would hurt - but it was the royal who was left wincing after the simple thumb-prick procedure.
On World Aids Day the pair chose to publicise the importance of being tested for the devastating virus by experiencing the test themselves during a visit to a HIV drop-in centre targeting men in Barbados' capital Bridgetown
The pair, who hugged each other and posed for pictures with their HIV counsellors, gave television interviews after their results came back negative.
With some Caribbean men reluctant to be tested because of the stigma surrounding HIV, Harry stressed: "The earlier you get tested the quicker you get on the medication. It's the stigma surrounding this that we have to break.
"There are a lot of issues around family dynamics and generational gaps that we have to get over, especially with men. We have a huge part to play in this. It's just that - normalising and destigmatising of the testing.
"Everyone can get tested even if they are in no danger of being potentially HIV positive."
The prince, who has been campaigning for more than a year to raise awareness about Aids, was publicly tested for HIV in the summer - giving a negative result.
Rihanna and Harry, who appeared on stage together on Wednesday night at the 50th anniversary celebrations over Barbados' independence, sat side by side as small drop of blood was taken from their thumbs by the HIV counsellors.
The prince winced as the pin was stuck into his thumb but after the same was done to Rihanna she laughed and said: "You made it seem like it hurts,'' adding: "It's not as painful as you said this morning.''
Harry, 32, persuaded the 28-year-old Bajan superstar to take the test when they chatted backstage last night, after the prince delivered a speech at a spectacular independence anniversary concert.
The two counsellors had explained to Rihanna and Harry the sort of questions they ask people about to undergo the test: questions such as how many sexual partners they have had in the past few months, whether there have been any new partners and whether they have had sex in the last two days.
While they waited for their results, the prince and the celebrity spent the next 20 minutes touring stalls set up in the centre of the capital to promote the Man Aware campaign, urging men in Barbados to get tested.
Aids workers worry that many Caribbean men are unaware that they are carrying the HIV virus and risk infecting others and becoming seriously ill because they refuse to get tested early due to the stigma surrounding the illness.
Around 1,500 people, or 0.6% of Barbados's population of 275,000, are thought to be HIV positive - but, as in Britain and elsewhere, there are many more who do not know they are infected.
Harry and Rihanna stopped at a makeshift barber shop set up in a small marquee, where one man was having a shave.
Fabian Sargeant, another HIV counsellor and social worker, explained that a barber shop was a perfect place to raise awareness of the need for HIV testing because it was where people discussed sex, friendship, and what was going on in their lives.
''I need to go to a barber shop'' Rihanna said to laughter. "Not for sex!'' she added quickly, wagging her finger and laughing.
Harry interjected: ''Everybody tells their hairdresser everything.''
Mr Sargeant explained that there were so many myths surrounding sex in Caribbean culture.
''One of the myths is that royalty don't have sex,'' he said, amid laughter.
''And that royalty has blue blood?'' Harry asked, perhaps hoping to change the subject.
''Another myth is that royalty does not engage in oral sex,'' Mr Sargeant said.
''I'm not sitting in that chair,'' Harry said, gesturing towards the barber, as those around him laughed.
Before leaving, Rihanna, famed for hits such as S&M and Umbrella, said of Harry: "I just think it's incredible what he is doing to bring awareness to HIV and Aids.
"The most important thing about this is ending the stigma surrounding the disease and knowing your status."
