As passersby approached the father-of-three, who donned the bright red vest and cap worn by regular vendors for his shift, the Prince had a special request for those eager to take a quick snap.
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The Big Issue reported that "lots of people want to shake hands, snap a selfie and have a chat, which William allows – only if they buy a magazine, of course".
The 39-year-old's temporary role selling the publication came just before the release of a special edition of the magazine which was published ahead of his 40th birthday on Tuesday.
The special edition was released the day before William's 40th birthday © Andy Parsons/ The Big Issue
The Prince made headlines after he paired up with regular vendor, Dave Martin, 60, to sell copies of the publication on Rochester Row, Victoria.
The duo sold 32 copies of the magazine in total, and William revealed that the experience was "truly eye opening" and made him feel "extremely lucky" to be a royal.
He exclusively told The Big Issue: "I count myself extremely lucky to have a role that allows me to meet people from all walks of life, and to understand their full story – whatever it may be.
William sold copies to the public © Andy Parsons/ The Big Issue
"It’s a privilege that many of us, busy with our days, don’t always afford.
"...So, for my part, I commit to continue doing what I can to shine a spotlight on this solvable issue not just today, but in the months and years to come. "
In the piece, William also paid homage to his mother Princess Diana, who he praised for encouraging him to help those in need, and pledged to do the same for his children, Prince George, Princess Charlotte and Prince Louis.
The Prince teamed up with long-standing seller Dave © Andy Parsons/ The Big Issue
He added: "I hope to bring George, Charlotte and Louis to see the fantastic organisations doing inspiring work to support those most in need – just as my mother did for me."
After his stint selling copies, the two men headed to The Passage, a charity which William has been a patron of since 2019.
Despite referring to himself as an "unlikely advocate" for the cause, William said he felt it was more important than ever before to show his support for such an important cause.
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