Murdo MacKinnon, from Kilmuir, credits Gillan with helping him raise almost £10,000 for the Alzheimer’s Society during her stay in Skye.
She went unnoticed among a crowd of family and friends who were in Portree Square to meet him at the end of a gruelling 500-mile walk from Fraserburgh.
The Jumanji star filmed his arrival, shared it and his fundraising page with her 7.6 million Instagram followers – then donated £500 herself.
“Nobody had noticed she was here. She had managed to keep herself completely incognito,” said Murdo, a postman in the Scottish Borders.
“She’d gone out of her way to film it, she’d gone out of her way to share it, she’d gone out of her way to donate,” he added.
“She didn’t have to do any of that…[I’m] just really humbled by the kindness.”