The Duchess of Cambridge arrived in a cream off-the-shoulder dress for a night at the museum.
Kate is joining guests from the arts and culture sector at the Natural History Museum in London for the Art Fund Museum of the Year Award.
The Duchess, who made the short journey from Kensington Palace, the Cambridges' London home, wore a mesh-panelled dress by Barbara Casasola, with strappy sandals and a sparkly clutch bag.
Kate, who is patron of the Natural History Museum, was greeted by its director Sir Michael Dixon, and Dr Stephen Deuchar, director of the Art Fund.
A £100,000 award, the largest museum prize in the world, is given annually to one outstanding museum which has shown exceptional imagination, innovation and achievement.
Among the artists in attendance are Cornelia Parker, Antony Gormley and Grayson Perry, who arrived in a sequinned purple, yellow and orange dress with flared sleeves, which he said was designed by Claire Cooper, one of his students at Central Saint Martins.
Kate spoke to representatives from the five museums shortlisted for this year's prize.
Nicky Wilson, of Jupiter Artland, West Lothian, said she was delighted to meet Kate, who told her Prince George has enjoyed a number of visits to the museum.
Ms Wilson said: "She said he comes here quite often. He loves the 3D sculptures."
The toddler, who will celebrate his third birthday later this month, has been spotted at the museum previously, admiring the dinosaurs on display.
The famous Diplodocus dinosaur, Dippy, forms the striking centrepiece for guests at the event, as they dine in Hintze Hall at tables set around the skeleton, which is illuminated in red.
The other four organisations on the shortlist for 2016 are: Arnolfini, Bristol; Bethlem Museum of the Mind, London; Victoria and Albert Museum (V&A), London; and the York Art Gallery, Yorkshire.