Prince William and Prince Harry told documentary makers that they didn't actually "have that many memories" of their mother.
The princes were interviewed by Nicolas Kent and Ashley Gething for the recent ITV documentary 'Diana, Our Mother: Her Life and Legacy' and Kent didn't realise how "candid" the pair were going to get about the loss of their mother, Princess Diana, who died in August 1997.
Kent told Vanity Fair magazine: "They prefaced their interviews by saying, 'We don't actually have that many memories of our mum.' One of the [side effects] of grief and bereavement is that memories kind of get suppressed or obliterated, so I don't think they knew, and we certainly didn't know until we began the interview that they would be so candid. But quite quickly when we began the interview, you could almost begin to see the memories surface."
In the documentary, Prince William and Prince Harry spoke openly about their relationship with their mother and Harry shared his "regret" at his last phone call with Diana.
He admitted: "As a kid I never enjoyed speaking to my parents on the phone. And we spent far too much time speaking on the phone rather than speaking to each other, because of the way the situation was. And the phone rang and off he [William] went to go and speak to her sort of for five minutes ... I can't really necessarily remember what I said, but all I do remember is probably, you know, regretting for the rest of my life how short the phone call was."
Whilst William added: "At the time Harry and I were running around minding our own business, you know, playing with our cousins and having a very good time ... I think Harry and I were just in a desperate rush to say goodbye, you know, see you later and we're going to go off. If I'd known now obviously what was going to happen, I wouldn't have been so blasé about it and everything else. But that phone call sticks in my mind quite, quite heavily."