There, the royal couple took a moment to admire a huge portrait of Princess Mary of Denmark, portrayed in a beautiful blue gown and sash across her shoulder.
William and Kate were visiting the museum as one of their final engagements on the couple's royal tour of Australia and neighbouring New Zealand, which will come to an end on Friday.
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Duchess Kate looks at the art on offer
In a lovely emerald green Catherine Walker coat dress, Kate, 32, looked stylish as she greeted the welcoming crowds that awaited her and her husband.
The mother-of-one accessorised with round diamond drop earrings and wore her brunette locks loose over her shoulders.
William and wife Catherine
As patron of the National Portrait Gallery back in her home of London, the Berkshire-born royal looked particularly thrilled to be visiting the museum and smiled and waved to the Canberra crowds who were stationed outside.
As Kate arrived, she was greeted by a young fan dressed in all pink, with a huge bouquet of flowers.
Kate gets a floral gift
Once inside, William and Kate were given the privilege of viewing the art on display and as they toured the exhibition, the Duchess admired the masterpieces and chatted eagerly to those around her.
Kate's first engagement of 2014: visit to London's National Portrait Gallery
Some of the subjects of the portraits — all of whom are well known, highly accomplished Australians in their respective fields — were on hand to discuss the art with their royal guests.
Back in 2013 when Kate was pregnant with baby George, she attended an event in honour of charity The Art Room in London. The brunette beauty delivered an inspirational speech in which said it felt "incredibly special" to be celebrating the organisation's work, which uses painting and drawing to build confidence and independence in young people.
Gallery: the royal baby in pictures
The couple are finishing up their visit to Australia
"I am a firm believer in the power of art to make a difference, and The Art Room is providing this on a daily basis," said Kate.
As a regular visitor to the National Portrait Gallery in London, the museum holds a special place in Kate's heart. The last time she attended a public engagement there was in February this year when she was guest of honour at a gala dinner.
Her most famous visit was perhaps to unveil her first official painted portrait in January 2013. Crafted by award-winning artist Paul Emsley, the artwork initially received some criticism but Kate was herself delighted with the result, calling it "brilliant, amazing, absolutely brilliant".