12/19/2011 03:09 pm ET | Updated Dec 19, 2011

Kate Middleton, The Duchess Of Cambridge, Dons Strapless Black Velvet Dress For Military Awards (PHOTOS)

It's a long, festive day for Kate Middleton! The Duchess of Cambridge arrived at Buckingham Palace today for her first Christmas lunch as a royal; then, at night, she and Wills attended the Millies, London's annual military awards show designed to recognize servicemen and women.

Earlier today, the royal couple attended a Christmas luncheon hosted by the Queen; Prince Harry, Prince Charles and Camilla were chauffeured to the lunch in a car, while Prince William chose to drive himself and Catherine (see pics at the Mirror, including Kate's burgundy coat).

And in the evening, Kate and Will arrived in stately glamour on the red carpet at the Imperial War Museum. The Duchess wore what appears to be a strapless velvet black gown, which she accessorized with sparkly earrings and a necklace that she reportedly received as wedding gifts. (We're hearing rumors the dress is Alexander McQueen -- a custom design, perhaps?) The crowning (pun intended) touch? Her long, wavy hair -- stunning.

Wills looked dapper in a classic black tux, and we're also spying Prince Harry playing the role of royal third wheel.

Kate, who was most recently spotted at Buckingham Palace in a green peace sign-printed Mulberry dress, has had a meteoric rise to sartorial fame this year -- we can't wait to see even more pics as she celebrates her first holiday season as a royal family member.

Check out the photos of Will and Kate below! We'll add more as they come in.