Prince William reveals how he talks to George and Charlotte about 'Granny Diana'

Prince William has revealed that he likes to talk to Prince George and Princess Charlotte about 'Granny Diana' so his children will grow up knowing about her.

The prince, along with his brother Prince Harry, has opened up about their mother's death, nearly 20 years ago, in a new documentary dedicated to her memory.

'I think constantly about Granny Diana,' William explains during the show. 'So we've got more photos up around the house now... it's hard because Catherine didn't know her, so cannot provide that level of detail.' 

'So I do, regularly, while putting George or Charlotte to bed, talk about her and just try and remind them that there are two grandmothers, there were two grandmothers in their lives.'

'It's important that they know who she was and that she existed.'

He adds that his mother instilled in him that a child's first few years are some of the most important.

'I want to make as much time and effort with George and Charlotte as I can because I realise these early years particularly are crucial for children, having seen, you know, what she did for us,' he says.

Prince Harry also talks about his relationship with Diana in the new documentary, Diana, Our Mother: Her Life and Legacy, which airs on ITV tonight.

'Our mother was a total kid through and through. She possessed a crazy laugh and was one of the most naughtiest of parents,' he admits, whilst Prince William agreed of her as a grandmother: 'She'd love the children to bits but she'd be an absolute nightmare. She'd come and go and she'd come in probably at bath time, cause an amazing amount of scene, bubbles everywhere, bathwater all over the place and then leave.'

William goes on to give an emotional tribute to his mother, saying: 'There are not many days that go by I don't think of her.'

'I have a smile every now and again when someone says something, and I think, 'that's exactly what she would have said', or, 'she would have enjoyed that comment.'

'So they always live with you, people you lose, like that. And my mother lives with me every day. I give thanks that I was lucky enough to be her son and I got to know her for the 15 years that I did.

'She gave us the right tools and has prepared us well for life in the best way she could, not, obviously, knowing what was going to happen.'