1 / 6

HRH The Duchess of Cambridge

HRH The Duchess of Cambridge is seen leaving Kensington Palace for the Diplomatic reception at Buckingham Palace on December 3, 2013.

Duchess of Cambridge shines in tiara at Diplomatic Reception

Shine from Yahoo Canada

The Duke and Duchess of Cambridge were out in full glamour last night to attend the Queen's annual Diplomatic Reception.

The white-tie affair took place at the Palace Ballroom at Buckingham Palace, and was the first such event the couple has attended together.

All eyes were on the new mum who was spotted leaving Kensington Palace with her husband in a chauffered Bentley, wearing the gorgeous Papyrus tiara formerly owned by the Queen Mother and Princess Margaret. Palace officials confirmed that the Queen had loaned the delicate piece to the former Kate Middleton for the event.

It's believed that this is the first time HRH has worn a tiara since her wedding to Prince William in 2011. The Duchess also wore a white Alexander McQueen dress, although sadly no photos of it have been spotted yet. -- by Caitlin McCormack