Princes William and Harry reveal Diana 'smothered' them with love

Princes William and Harry have offered a rare glimpse into their relationship with their late mother Princess Diana, in an authorised documentary marking the 20th anniversary of her passing.

A trailer for the documentary, Diana, Our Mother: Her Life and Legacy, produced by American cable company HBO, shows the brothers discussing the contents of a photo album assembled by Diana.

“This is the first time that the two of us have ever spoken about her as a mother,” Prince Harry says.

“She was very informal, and really enjoyed the laughter and the fun,” Prince William adds, in tribute to the monarch who was well-known for her humanitarian efforts.

“She was one of the naughtiest parents. But she understood there was a real life outside of the palace walls.”

“She was our mum. She still is our mum,” Prince William adds.

“And of course, as a son I would say this – she was the best mum in the world.

“She smothered us with love – that’s for sure.”

The film promises to show Princess Diana “in a way she has never been seen before, through the eyes of the two people who knew her best”, executive producer Nick Kent said in a statement.

In April, Prince Harry revealed he suffered two years of “total chaos” while struggling to come to terms with his mother’s tragic death in a car crash.