Den Kongelige Gæst (English: The Royal Guest) is an opera in one act by Hakon Børresen; the libretto is by Svend Leopold, and is based on a story by Henrik Pontoppidan.

The story plays out an evening in a doctor's home on the Jutland peninsula around 1900.

Dr. Høyer and his wife are expecting guests for a dress ball.

However, all the guests decline at the last moment, and Dr. Høyer is irritated, but slightly relieved.

Instead, the family receives a surprise visitor, the unknown gentleman Prince Carnival, who acts in a free and easy manner, playing the piano, talking with Dr. Hoyer's wife, and suggesting to the couple to carry on with the party.