Known for her frugal approach to fashion, eagle eyed royal fans noted that Kate had also worn the Jimmy Choo high heels before, for her and Prince William's appearance at the BAFTA awards in February.
Kate has carved a reputation for recycling her royal outfits, and is regularly photographed in her go-to staples like one of her beloved Alexander McQueen coat dresses, her striking L.K. Bennett skirt suits or her tried and tested floor length Jenny Packham dress which the Duchess wore three times between October 2013 and December 2014, Vogue Australia notes.
The future Queen consort is also a frequent wearer of New Zealand-born designer Emilia Wickstead, London brand Temperley and French-born fashion creator Catherine Walker.
Kate's mother-in-law the late Princess Diana was a huge fan of Catherine Walker, who was known to have supplied over 1,000 for the Princess of Wales.
Diana was famously laid to rest in a black Catherine Walker dress after her tragic death in Paris in 1997.
The gala dinner was hosted by chef Skye Gyngell and British charity Action on Addiction, which the Duchess has been patron of since 2012.
Kate delivered a touching speech recognising the work of the charity, noting: "What's remarkable about Action on Addiction is that it goes beyond helping those who are suffering on the courageous journey into recovery - but it also lends direct support to the children and families affected by addiction – for as long as it takes.
"There was never a more important time for Action on Addiction to succeed. And I, for one, could not be more delighted to support such a special organisation."
Later, she also met with former members of Action on Addiction who were helping out in the Spring kitchen.
One day earlier, William and Kate spent the afternoon in Cumbria where they celebrated the "resilience and spirit" or rural British farming communities, and were introduced to first responders, young people trained as mental health first aiders and officers from Cumbria's mountain rescue service.
The royal couple played with a seven-month-old therapy dog called Prince Harry, named after the Duke of Sussex, and documented the day out on their official Kensington Palace Instagram account.
It's been a busy week for the Cambridges who were at Buckingham Palace on Saturday for the Queen's birthday parade at Trooping the Colour.
England's future King and his Queen consort joined senior members of the royal family including Prince Charles and Camilla, Duchess of Cornwall to watch the RAF flypast in celebration of Her Majesty Queen Elizabeth's 93rd birthday.
And while the Queen's husband Prince Philip was notably absent, no doubt gearing up for his own 98th birthday on Monday, Meghan Markle, Duchess of Sussex made her first public appearance since introducing her royal baby Archie Harrison with a photocall at St George's Hall in Windsor last month.