Jack and Stanleigh will be cutting off a combined total of 30 inches of hair at Beatties Barbers and donating it to the charity on Thursday July 20.
Mum, Emma-Jayne Morris, said: “Those of you who know the boys will know that this is a huge deal for them as they absolutely love their long locks and have never had a proper haircut before in their lives.
“But we are incredibly proud of them for volunteering to do something to help other children feel better in themselves and more confident.”
As well as donating their hair, the brothers are hoping to raise as much money as they can for The Little Princess Trust as it costs £550 to make a single wig for a child who has lost their hair.
So far, Jack and Stanleigh have raised £285 of their £550 target.
You can donate by going to https://www.justgiving.com/page/jackandstanleighsbigchop