William asked why Elton and David wore rings and whether they were a couple.
And Paul, who witnessed the meeting, says Di sensitively took the heir to the throne aside and told him men had relationships and lived together like other couples.
“Diana told the boys Elton and David lived together like a man and woman – that they shared a deep love ,” said Paul.
“It was incredible to witness the education of William in this way. Elton himself had helped Diana understand the world of HIV and AIDS and how the Princess could help bring greater compassion and understanding to those who were suffering.
“Elton gave Diana an education at a time when it was frowned upon to even shake the hand of someone who had either HIV and AIDS.
“Diana did this because she cared. She surrounded herself with people who were like-minded and who she was comfortable with.
“Elton John, David Furnish and George Michael became confidantes. It wasn’t because they were gay, it was because they were good, kind human beings like her and wanted to make a difference in the world.”