Out singer and AIDS activist Elton John has praised Prince Harry for showing the world how “easy and simple it is to take an HIV test.”

The entire test was broadcast live on the royal family's Facebook page.

“In 1991, Princess Diana moved a mountain by addressing the stigma surrounding people living with HIV/AIDS,” Elton John said in an Instagram post. “She showed the world we could safely wrap our arms around AIDS patients, by shaking hands with a patient without gloves. We've made huge strides since then in the treatment of the disease. People now live long, happy lives with HIV, when the virus is effectively managed with anti-retrovirals. Despite this amazing progress, most people today are still frightened and stigmatised at the notion of taking an HIV test. Today in London, Prince Harry gave that stigma a knock on the head by showing the world how easy and simple it is to take an HIV test. Bravo Prince Harry! Your mother would be so proud of you. @ejaf #LoveBravery.”

Prince Harry, 31, took a so-called instant test that reveals a person's HIV status from a small blood sample in about one minute. Harry's test came back negative. The test took place at Guy's and St. Thomas' Hospital in London.

Harry co-founded the HIV/AIDS charity Sentebale in memory of his mother, Princess Diana, and is working to increase awareness of the disease.

“Gay, straight, black, white, ginger, whatever – why wouldn't you just have a test?” he told viewers. “It should be normalized. Everybody should get it.”

Prince Harry and Elton John are scheduled to speak at next week's International AIDS Conference in Durban, South Africa.