The Duchess attended Diplomatic reception

Last night the Duchess of Cambridge attended annual Diplomatic reception hold in Buckingham Palace. The dress code was 'white tie' which means Ladies have to wear tiara and floor length gown.
Kate opted out for the pale blue Alexander McQueen dress she wore in 2013, the Queen diamond drop earrings and diamond and pearl Cambridge Lover's knot tiara.

I assume she also wore her favourite Jimmy Choo 'Vamp' metal sandals.