More than 40 firefighters were called to the 14th century Star Inn at Harome, near Helmsley, North Yorkshire, which has been cited as one of the best in the UK.
Chef Andrew Pern said on Twitter: "It's been a long night so far.... I'm afraid we won't be open for a while as we are reduced to ashes with The Star on fire and still burning, residents please call after 9 am . Thanks [email protected]"
North Yorkshire Fire and Rescue said nine appliances from Helmsley, Kirkbymoorside and Pickering were called to tackle the burning thatched roof and seven remained at the scene on Thursday morning.
A spokesman said: "All the occupants of the property were out on the arrival of crews.
At its peak the incident had nine appliances, one aerial ladder platform, one water bowser, one welfare unit and an incident command unit in attendance.
"Crews worked with main jets and hose reel jets to contain the fire and the aerial ladder platform was deployed to removed thatch from the roof.
The incident was scaled back to seven fire engines and the aerial ladder platform at around 5.45am. The incident is still ongoing and crews are still working to extinguish the fire in the roof using hose reel jets and 45 jets."
The Star at Harome has regularly featured in lists of the best restaurants and gastropubs since the arrival of chef and patron Mr Pern 25 years ago.