Prince William, 41, was reunited with Big Issue seller Dave Martin at his pitch in London.
Images of the royal wearing a Big Issue tabard and matching baseball cap circulated on social media earlier in the day and Kensington Palace later shared a snap of William with his arm around Dave on their social media accounts.
“Great to be back with Dave, selling the latest edition of the @BigIssue once again!” the caption read.
HELLO! understands that the Prince helped Dave to sell issues of the latest magazine, and the pair even exchanged Christmas cards.
William first met Dave last summer ahead of the royal's 40th birthday, when he went undercover as a Big Issue seller.
Big Issue founder Lord John Bird says: "We are very lucky to have the Prince of Wales throwing his support our way yet again. It's grand to have this huge level of awareness that HRH brings, especially at a time when thousands of our vendors are facing the crushing pressures of escalating costs and are working hard, often out in terrible weather conditions. Please do support your local vendor and buy a copy of the magazine."
Dave was also invited to the launch of the Prince's Homewards project in June, which aims to eradicate homelessness in the UK.
Learn more about the initiative in the clip below...
"I think it’s really personal to [William]," Dave said at the launch of the initiative. "His mother used to go to The Passage – that’s where he experienced homelessness for the first time, that’s why it’s really important to him."
The five-year project will initially focus on six locations where local businesses, organisations and individuals will be encouraged to join forces and develop action plans to tackle homelessness with up to £500,000 in funding.
William recalled his visits to The Passage with his late mother, Diana, Princess of Wales in 1993, saying: "My first visit to a homelessness shelter was when I was 11, with my mother. The visits we made left a deep and lasting impression. I met so many extraordinary people and listened to so many heart-breaking personal stories. Too many people have found themselves without a stable and permanent place to call home."
Earlier in the day, Kate, 41, also stepped out to open a new children's day surgery unit at Evelina London Children's Hospital.
LISTEN: How Prince William supported Kate when she joined the royal family