The trio made the appearance to partake in The 2011 Sun Military Awards, which is held as a toast to the unsung military heroes hailing from Britain.
Aside from the glitzy event, Will and Kate recently learned that they'd raised over $1.5 million in one day for famine victims in East Africa by publicizing a Unicef appeal.
"The Duke and Duchess are delighted to hear of the overwhelming generosity of the British public,' said a spokesman. "They remain hugely concerned for the children still at risk, but view this as extremely welcome news."
Enjoy the pictures of Prince William, Kate Middleton and Prince Harry attend The Sun Military Awards (December 19).