Donald and Melania Trump Meet Royal Family at Windsor Castle

Donald Trump and his wife, Melania, are in for some royal treatment ... meeting with the British Royal Family at Windsor Castle.

The President and First Lady touched down Wednesday via helicopter, where they were immediately greeted by Prince William and Kate Middleton at the Walled Garden.

From there, the Prince and Princess of Wales brought the Trumps to Victoria House for a sit-down with King Charles and Queen Camilla. The Queen is in attendance despite recently falling ill due to "acute sinusitis" ... and it marks the first face-to-face between DT and Charles since he took the throne.

The Trumps are cashing in on royal perks ... riding in a carriage procession with the Royals before chowing down for lunch in the State Dining Room.

Donald and Melania will privately pay their respects to Queen Elizabeth II's tomb ... followed by a special Beating Retreat military ceremony.

Festivities will cap off with King Charles hosting a state banquet for the Prez and First Lady, where he'll give a speech.

While the Royal Family is rolling out the red carpet for the Trumps ... not everyone in Windsor's giving DT a warm welcome. Images of Donald Trump alongside Jeffrey Epstein were projected on Windsor Castle Tuesday night ... and the stunt led to four arrests.