Brave 12-year-old Rachel Gower will carry the Olympic Torch in memory of her brother who was chosen as a torchbearer before his death from cancer.
Geoffrey, 14, lost his fight against the disease in February. He had been due to carry the torch on a leg of its journey through Hemel Hempstead on July 8.
Torch relay organisers have allowed Rachel to take over his role as a tribute.
Mum Anne said: “She is very happy and very pleased. She feels very privileged they are allowing her to do it in Geoffrey’s memory.
“It’s going to be an emotional time. It will be five months to the day that Geoffrey died.
“Lots of people will be out there for Rachel but thinking of Geoffrey. I would not be surprised if there are a few tears along the way.
“It was something he was really looking forward to doing.”
Geoffrey suffered from a rare lower spinal tumour. He was first diagnosed when he was 10.
He was a pupil at The John F Kennedy School in the town and fellow pupils are expected to line the route along with family members.
Anne added: “I think we could have a whole section to ourselves.”
The Flame will arrive in Hemel Hempstead at around 5pm on Sunday 8 July on Leverstock Green Road, continuing onto St Albans Road. It will travel onto Leighton Buzzard Road, through the Marlowes and onto Queensway before travelling to its next destination. Residents have been encouraged to line the streets for the event.