The Duke and Duchess Of Cambridge were pictured arriving at the Natural History Museum in London to watch David Attenborough's Natural History Museum Alive.
Kate, who gave birth to son George in July, showed off her slender post-baby figure in a long cream dress with black lace overlay, which was clinched in at the waist with a black velvet belt.
The mum-of-one's frock featured long-sleeves and a flared skirt, making it perfect for a chilly festive evening, and she styled her brunette locks into a glossy and straight style.
William, meanwhile, looked very dapper in a black suit, white shirt and bow tie.
Leaving George at home with a sitter, Kate and William looked relaxed and shared a joke as they made their way into the venue to watch the 3D movie.
This is the second premiere in a week that the Royal couple have attended, as they were pictured at the opening night of Mandela: Long Road To Freedom on Thursday (5 December).
As reported on Reveal.co.uk, the evening was touched with sadness, however, as Kate and William were told during the film that Nelson Mandela - who the movie is based on - had passed away in South Africa.