Adam Jackson, head chef at the Michelin-starred Black Swan at Oldstead, has left to start his own venture.
Jackson helped the Yorkshire pub to win its first star in 2012 - a feat it repeated in 2013.
The business also has three AA rosettes and was voted AA pub of the year in England in 2010. It is owned by the Banks family from Oldstead Grange, who bought the it in 2006, and have lived and farmed in Oldstead for generations.
Tommy Banks, currently sous chef, and son of co-owners Tom and Anne Banks, is understood to be stepping up to run the kitchen following Jackson's departure. His brother James runs the front of house.
Meanwhile, Jackson is set to launch a new business in Sutton on the Forest in North Yorkshire, the details of which have not yet been revealed.