Running from April 1-3, the fair takes place throughout the servant quarters downstairs of the impressive home and up across its grand state rooms including The Stone Hall and The Salon.
The Harrogate-based organiser is keen to point out that visitors can visit every room in the house as well as its gardens.
Duncombe Park stands in 300 acres of parkland next to the town of Helmsley.
The original house was built in 1713 for Thomas Duncombe, and following a fire in 1879 the first Earl of Feversham remodelled the interiors.
After the death of the second Earl of Feversham at the Somme in 1916, Duncombe Park was leased as a girls’ school, but was returned to a family home in 1985 when it was restored and refurbished.