The film aims to raise awareness of the needs of children who have lost a parent and parents who have lost a child.
The video opens with a young boy saying: “If I had one more minute, I would tell her: ‘I still wanted you to be with me’”.
The film includes children, teenagers, a widowed parent, and a bereaved couple.
Another child said: “I would just say I love you, because I didn’t have the chance to.”
The charity’s patrons and celebrities who have also suffered a bereavement are also featured including Mary Berry, Jason Watkins and Rio Ferdinand.
The Duke of Cambridge provides a final message in the film.
“Please, take one more minute to support Child Bereavement UK and help rebuild lives of bereaved families,” he said.
Child Bereavement UK’s chief executive, Ann Chalmers, explained the idea behind the campaign is that it “taps into a human truth that will help people to understand the impact of bereavement”.
“The film touches on the longing that many bereaved families tell us they have, to be able to have more time with the person who has died,” she said.
“In our 23 years’ experience of supporting children, young people and families, this is something that is commonly expressed and that many people will relate to.”
Rio Ferdinand, whose wife Rebecca died in 2015, said: “I think the work that Child Bereavement UK do is phenomenal.
“The environment I’m from doesn’t do reaching out and emotional talking. Once I had broken that down and realised that I needed that help to help my children, I saw the benefit straight away.”
People are being invited to upload their own ‘One More Minute’ films by tagging Child Bereavement UK on social media and using the hashtag #onemoreminute.
The TV advert will be aired on Channel 5 on Friday 20 October at 8pm.
Visitors to www.onemoreminute.org can watch the films, find out how to seek bereavement support or make a donation to support the charity’s work.