As the striking images of life during lockdown go on display in 80 towns and cities across the UK, Prince William and Kate donned facemasks and headed to Waterloo to meet Hackey Food Hub volunteer Sami Massalami Mohammed Elmassalami Ayed, who featured in the image "Sami", taken by Grey Hutton.
WATCH: Prince William and Kate Middleton meet finalists from the Hold Still photography project
Sami, a volunteer at a community Food Hub in Hackney, revealed he didn't know that his picture had been submitted by one of his colleagues until he got a call from the National Portrait Gallery.
He said: "The Duchess called me a few weeks ago and we had such a lovely conversation. She told me how she wanted to build a snapshot of how Britain was coping in the pandemic, but to show all sides of what people have gone through and are still going through."
Sami, who is visiting the UK until October while studying for a PHD in London, said: "The Duchess came across as really caring and dedicated, I was so impressed she took the time to call me.
"I told her about the work they do at the food hub, and she agreed it’s such a vital project. I was lucky enough to help out there for a couple of months, but they always need help throughout the year."
Keep clicking for more photos...
They also visited St Bart's Hospital to meet Joyce Duah, who took the photograph "All in this Together." Joyce, who is a specialist oncology pharmacist, photographed colleagues Amelia Chowdhury and Dipal Samuel, who were drafted in to work as pharmacy technicians in the Intensive Care Unit.
The striking image taken by Joyce at the height of the COVID-19 crisis earlier this yar, showed her colleagues writing their names, smiley faces and love hearts on their disposable PPE aprons.
The Duchess said: "Thank you so much for the image. It had such an impact it captured the moment, it was a look behind the scenes. The story of what you experienced is so important."
The Duke added: "It is important for history purposes to show that actually happened."
Joyce, who shielded patients on the hospital's cancer ward, said after her meeting with the royals: "I married photography and care together. I took a series of photos of them getting into and out of their PPE. I thought it was the most interesting aspect.
"It shows Amelia and Dipal writing their names with a marker on each other's PPE because when a patient wakes up, they know our names. It was a very touching sentiment.
"Patients were often in a coma and so coming round confused and didn't know who was treating them. But also we couldn't even recognise each other at times without names."
The Duchess looked autumnal in a long, red double-breasted coat by fashion favourite Alexander McQueen for her outing. She teamed her bold outerwear with a white blouse, a black pleated midi skirt and heels, and accessorised with a new Grace Han bag.
The Duchess, a keen amateur photographer, launched Hold Still in May in collaboration with the National Portrait Gallery, of which she is patron. She helped to select 100 finalists from 31,000 entries and unveiled them in the National Portrait Gallery’s digital exhibition in September.
From today, the photographs will appear on billboards, bus stops, train stations and shop fronts for the next four weeks.
One of the portraits "Melanie, March 2020", showing NHS nurse Melanie Senior and taken by Johannah Churchill, has been recreated as a hand-painted mural in Manchester city centre.
All 100 portraits will also feature in a special exhibition hosted by the National Memorial Arboretum in Staffordshire from 23rd October.
The exhibition is being backed by the Co-op which launched "Co-operate" in April to help connect vulnerable people to local and national support initiatives and has recently provided emergency relief funding to 4,500 community causes.