Catherine also paired the looked with a unseen Art Deco diamond brooch.
The Remembrance event comes four days after Catherine gave one of her red poppies to a young royal fan.
During her inaugural visit to Colham Manor Children's Centre in Hillingdon, west London, the Princess of Wales was greeted by a chatty boy named Akeem, and the patron of the Maternal Mental Health Alliance was more than happy to oblige in a conversation with the three-year-old.
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"My name is Catherine," the royal introduced herself after Akeem inquired. "Very nice to meet you," she continued.
The Duchess of Cornwall then asked if Akeem had a poppy, before offering her own to the young boy.
"You can have my poppy," she said as she removed it from her coat.
"Do you know what this is for?" Catherine asked as she handed Akeem the poppy. "It's remembering all the soldiers who died in the war.
"There you go that's for you, you look after it," she continued. "Is there a teacher here or your mummy? Is your mmmy here? Shall I give her the pin in case she wants to put it on?"
This article was first published on our sister site Now To Love.