Prince William and Kate Middleton‘s kids are feeling festive.

Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5, joined their parents at the Together At Christmas Carol Service at Westminster Abbey in London Dec. 8.

For the occasion, Kate, who hosted the charity event supported by The Royal Foundation, donned an all-white ensemble featuring—with a long white Catherine Walker coat over a sweater and a pair of high-waisted Holland Cooper pants. The Prince of Wales, George and Louis twinned in navy suits, while Charlotte sported a burgundy, wool dress coat and black tights—the same outfit she wore to last year’s service. 

During this year’s event, which also benefited the Royal Foundation Centre for Early Childhood, George, Charlotte and Louis were all seen depositing letters in a red post box was set up to collect cards and messages from the church’s congregation to be given to children in need.