Kate visited the Victoria and Albert Museum to see the Fabergé in London: Romance and Revolution display, which celebrates the work of Carl Fabergé, the genius behind the world-famous Russian jewellery house.
Wearing black wide-legged trousers and a patterned pussybow blouse, the duchess also put on a black face mask.
Kate became the first Royal Patron of the V&A in March 2018 and last visited in May this year to mark its reopening after the pandemic forced galleries, museums and art attractions to close for months.
During her latest trip to the museum, she congratulated those behind the display, which features the largest collection of Faberge's well-known Imperial Easter Eggs in a generation, several of which are being shown in the UK for the first time.
The duchess was accompanied on her tour, which lasted just under an hour, by V&A director Tristram Hunt and shown around by curator Kieran McCarthy.
Speaking after the visit, Mr McCarthy said Kate had been "fascinated by the whole subject".
The duchess, who is known to be a keen photographer, showed her clear eye for detail, he added.
"That came through over and over again, just 'How did they do that? Why does that look like that?'
"There was a lot of why and wherefore in the discussion, which was very interesting because it takes a sophistication to look beyond seeing the spectacle to actually probe into the details, and that was there."
The collection features items lent by The Queen, including the Colonnade Egg, the Basket Of Flowers Egg and the Mosaic Egg.
Admiring the Peacock Egg, which features an enamelled gold peacock perched on a flowering tree, Kate could be heard to say "I love the tree".
The exhibition, which opened on November 20, showcases more than 200 objects and celebrates the work of Faberge and his internationally recognised company.
Other items include the long lost Third Imperial Egg, which was discovered by a scrap dealer in 2011 after going missing in 1964.
The largest Imperial Egg - the Moscow Kremlin Egg - is also among the collection, as well as the Alexander Palace Egg, which contains a model of the palace inside.
During the visit, Kate, who at times bent down to get a closer look at the items on display, was informed about Faberge's works and the relatively unknown Anglo-Russian nature of his enterprise, with his only branch outside Russia opening in London in 1903.
Before leaving, she told Mr McCarthy "Well done" and asked him to pass on her thanks to his team.
The Faberge exhibition runs until May 8 next year.