The Duchess also saw Johannah Churchill's framed picture entitled "Melanie, March 2020", an image of her fellow nurse wearing personal protective equipment and helping to prepare a Covid-19 clinic for patients.
The picture was recreated as a powerful mural in Manchester and is the cover image of the book Hold Still.
Kate and the National Portrait Gallery gifted the framed portrait to the Royal London and it will go in display in the hospital's main corridor.
Looking at the portrait, she said: "It's become really iconic, hasn't it?
"Some of them had really powerful stories behind them and this one really stood out.
"I spoke to Johannah and she was so, 'this is not about me, it’s about the people who I represent'. She was so humble about it."
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