He opened up about his grief in an emotional conversation with a mother who lost both her young son and husband within days.
'The shock is the biggest thing, and I still feel it 20 years later about my mother. 'People think shock can't last that long, but it does. It's such an unbelievably big moment in your life and it never leaves you, you just learn to deal with it.'
The second in line to the English throne followed in the footsteps of his younger brother Prince Harry who gave an emotional interview this week in which he revealed he sought professional help four years ago after struggling with the grief of Diana's death in August 1997.