ITV will air a “unique, landmark documentary” celebrating the life and work of Diana, Princess of Wales later this year.

Marking the 20th year since her tragic death, the film from the producers of ITV’s Our Queen at 90 will feature contributions from The Duke of Cambridge and Prince Harry, both of whom talk openly about their mother and how her influence has shaped their lives.

Their Royal Highnesses will also offer their perspective on The Princess’ unique contribution to public life, including her charitable and humanitarian work. Areas including Landmines, Child Bereavement, Homelessness and HIV and AIDS, will be explored.

Jo Clinton-Davis, ITV’s Controller of Factual commented: “This new ITV film will offer viewers a fresh and revealing insight into Princess Diana through the personal and intimate reflections of her two sons and of her friends and family, many of whom have never spoken before, to bring together a definitive portrait of a unique person who touched the lives of millions.”

Executive producer Nick Kent added: “This film will show Princess Diana in a way she has never been seen before, through the eyes of the two people who knew her best.”