Images taken by Yorkshire Post photographer Steve Riding show that part of the 14th-century inn's thatched roof has been completely destroyed, though other sections of the building appear to have escaped serious damage.
North Yorkshire Fire and Rescue Service investigators are now at the scene to ascertain the cause of the fire.
It began in the roof, but fire crews managed to save one end of it and the ground floor from igniting.
Mr Pern owns three restaurants, and his York business, The Star Inn the City, had to close for several months after a kitchen fire in November 2018.
The Star is the fifth country pub in North Yorkshire to have suffered a significant fire since July 2020.