"Four generations of the royal family have come together to support The Royal British Legion's 'Together at Christmas' initiative," reads the caption for an image of 6-year-old George stirring the contents of a bowl while his older relatives smile and watch.
A Christmas tree can be seen behind them.
Another photo shows Charles and WIlliam helping out George, while the monarch supervises.
"The queen, the Prince of Wales, the Duke of Cambridge and Prince George, joined forces to prepare special Royal British Legion Christmas puddings at Buckingham Palace this week," reads a message accompanying the group shot.
The initiative is intended to host get-togethers for military veterans during the winter holidays.
"It is hoped that they will provide a sense of community and companionship to help combat the loneliness and isolation experienced by some members of the Armed Forces community over festive periods," the family's website said.