Dunedin boy Harry Willis has been practicing every day to pogo-stick up the world's steepest street in honour of his ill sister.
Tomorrow, the 11-year-old will attempt to bounce up Baldwin St to raise money for Ronald McDonald House in Christchurch for housing him and his famliy when his four-year-old sister Darcie was in the child cancer ward at Christchurch Hospital for six months.
Last year, Darcie was diagnosed with a highly aggressive form of Burkitt's lymphoma - a fast-growing cancer of the lymphatic system.
She is now at home in good health and no longer receiving treatment.
Her diagnosis came just six months after the family moved to New Zealand from Australia for a fresh start, after baby sister Maggie died shortly after birth in 2015.
Parents Stephen and Cheryl Willis described the shift as Maggie's legacy.
Harry says he came up with the idea to say thanks to Ronald McDonald House.
"Well, my sister died a couple of years before, so it made it a bit more hard, because I wanted to spend as much time with Darcie. I was sad and worried that she could die.
"I wanted to do this to say thanks to Ronald McDonald House, because Darcie was in hospital for six months. She came to Ronald McDonald House when she was able to come out of the hospital, and they also gave us food for the night and the whole day.
"Because we live in Dunedin, they also provided a room for us to come and stay."
He has been training for the attempt and was "really confident" he could do it, practicing for 25 minutes every day.
"I have been training hard," he says. "I've been doing bits of Baldwin St and I've been doing streets that are near the street [Baldwin St].
"I'm really confident, because on other streets, I can do it on the first go."
With a special black-and-red pogo-stick ordered in from the United States, Harry thinks he'll be able to complete the feat in 15 minutes and isn't allowed to put his feet down at any stage.
Out of all his friends, he was the best at pogoing, he says.
"Well, I'm the only one that's good at pogo-sticking. I sometimes take it to school and let some of my friends have a go, but they're not as good as me."
Baldwin St is recognised by the Guinness Book of Records as the world's steepest residential street and has been the location for the annual Cadbury Jaffa Race.
The whole family will watch the attempt, including brother Jesse, 8, baby brother Alby, and his grandmother who came over from Australia.
So far, Harry has raised $3758.74 and aims to reach $5000 to donate to Ronald McDonald House.