Prince Harry is set to reveal one of his secrets today as part of a campaign to help reduce stigma associated with HIV.
The royal will be joined by stars including Nicole Scherzinger, Gemma Arterton and Paloma Faith, who will all lay their secrets bare to the world on video in support of Sentebale's #FeelNoShame campaign for World Aids Day.
Harry co-founded his Sentebale organisation in Lesotho two years after travelling around the country in 2004 and seeing for himself the problems faced by Aids orphans, disabled children and others with serious issues.
Prince Harry will reveal all in a video later
He said: "To show our support for the children of Lesotho, and help reduce the stigma for all those affected by HIV, we are turning this World Aids Day into a day in which no-one should feel any shame about their secrets.
"Together, we can tackle the stigma surrounding HIV and give the young people carrying it the childhood they deserve. The childhood so many of us take for granted."
Sharing secrets from worst fears to guilty pleasures, Harry and the A-List line-up hope to raise awareness of the stigma and shame which prevents HIV sufferers worldwide from speaking up and seeking support.
The 30-year-old said: "Globally, HIV is the second-highest cause of death amongst those aged between 10-19 years old, and it is the number one cause of death across Africa.
"One tragic issue in particular is the shame and stigma linked to HIV.
"This causes thousands of children to needlessly die each year because they're keeping their illness a secret and not getting the medical attention they need."
The campaign aims to raise awareness of how eradicating shame and stigma can save the lives of HIV sufferers, empowering them to seek medical support and education about their condition, and preventing the virus from spreading.
Harry launched the campaign himself at midnight, releasing a video from a microsite - FeelNoShame.Today - asking the public to share their own secrets via social media in exchange for his.
He will release a second video at 1pm sharing his secret while other celebrities' secrets will be released throughout the day via the same microsite.
Cathy Ferrier, chief executive officer of Sentebale, said: "Too many children are not receiving the treatment and care they so desperately need due to the stigma attached to HIV.
"Today we will celebrate the sharing of secrets with #FeelNoShame to help spread the word that eradicating the stigma surrounding HIV will help save the lives of many HIV-positive children."
Prince Harry co-founded Sentebale in 2006 with Prince Seeiso of Lesotho.
Lesotho has the third highest HIV/Aids prevalence in the world after Swaziland and Botswana.
More than 37,000 of Lesotho's 500,000 children are HIV positive and approximately 200,000 have lost parents to Aids, forcing them out of school and into hazardous forms of labour including prostitution and trafficking.
Since 1996, the country's average life expectancy has fallen from 59 years to below 48.7 years.
Sentebale provides accommodation, hot food, access to medication and education for Lesotho's children, as well as vital psycho-social support to help them tackle stigma and cope with the emotional repercussions of their condition and live normal lives.