Seven-year-old Sam Cohen will run the 1k with his younger brothers for Jewish Care after befriending two of its clients.
The Rosh Pinah Primary pupil has bonded with Matthew Kayne and Simon Davies, residents of Rela Gold-hill Lodge in Golders Green, caring for those with physical or sensory disabilities.
Sam's mother, Nicki, a Jewish Care marketing executive, said: "The first thing Simon did was offer Sam chocolate, so that was the way to his heart. And he was really taken with Matthew.
"It was his first experience of meeting anyone with a serious disability and I was so impressed that rather than being scared, he just tried to get Matthew to laugh and high-five him."
After she suggested that Sam might like to run to raise money for Jewish Care, he enlisted brothers Jake, 5, and Rafi, 2, in the enterprise.
Ms Cohen is "really proud" of her sons, who set themselves a target of £100, but have already raised more than £650.
As for Sam, she said: "It's really great for him to learn that not all people are as fortunate as him and to meet people who are doing so much with their lives despite their disabilities."
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