Kate Middleton, Duchess of Cambridge, attended a film screening with Prince William this evening at the Natural History Museum in London. The Duchess wore her beloved Temperley London black lace gown for the occasion, previously seen at two events in 2012. Thrifty Kate strikes again!

Clearly a huge fan of Temperley's designs, Kate and her sister Pippa both wear the British designer often. Kate first wore the black gown from tonight to attend the premiere of War Horse in London, and then later while she and William visited St. Andrew's University during its 600th Anniversary, where they met. At these two events, Kate accessorized differently, choosing a black clutch for the War Horse premiere and her red Alexander McQueen clutch while at St. Andrew's. The visit to their Alma Mater was also in advance of Remembrance Sunday 2012, so Kate's red bag matched her bright Poppy pin perfectly.

The love for Temperley London goes both ways -- as earlier this week Alice Temperley gushed that the Duchess is "the perfect modern-day woman," and a great champion of British fashion. We must agree, as anything Kate wears (which is typically by a British brand) flies off shelves -- yes, even multi-thousand dollar dresses!

The film screening tonight was a 3D production: David Attenborough's Natural History Museum Alive. So yes, the Duke and Duchess had to wear 3D glasses, and what better accessory to go with Kate's diamond bracelet and William's bow tie?! The pair seemed to be having a lot of fun on their date night. (But why don't they get fancy 3D glasses? Ours for Titanic 3D were WAY cooler...)

Photo: WPA Pool/Getty Images

Click through the gallery above for more photos of Kate and William's evening!