When Thomas Moore, from Maryland, US, was eight, he saw his mum watching a video about a young girl who was battling cancer and had lost all her hair.
At the time, he didn’t understand why she was bald. His mum, Angie Pulos, explained the girl was having chemotherapy and hair loss was a side effect.
Thomas told his family he wanted to help the girl and so started growing his hair.
After two years, he’s donated enough to make three wigs for children with cancer.
Thomas’ aunt, Amber Lynne, tweeted a photo of her nephew on Sunday 11 September to show his hair before and after the cut.
“He was feeling nervous about getting the cut, wondering what he would look like,” Lynne told BuzzFeed News.
But Thomas had no reason to be nervous. The tweet was liked more than 113,000 times in five days and retweeted more than 50,000 times.
People have responded to Lynne’s tweets with heartwarming messages for the 10-year-old, telling him how “brave” “kind” and “beautiful” he is.