The eatery is housed in the Grade II-listed former St John's Court Hall on Whiteladies Road which has recently been converted after a building society operated on the site for more than two decades.
"The best seasonal local produce is always at the heart of the River Cottage approach to cooking," said the chef and food campaigner. "We are very much looking forward to celebrating and contributing to the vibrancy of the local food community in Bristol," he added.
When the doors open, the Bristol restaurant will be the third River Cottage Canteen and the first new opening under the concept in more than a year.
The first restaurant and deli under the Canteen brand opened in Axminster after Fearnley-Whittingstall used the former pub as a base for his Chicken Out! TV campaign.
Local produce
Up to 90 per cent of the produce on the daily-changing menu in the Bristol restaurant will come from within a 50-mile radius of the venue. Suppliers already confirmed include the Community Farm in Chew Magna which will supply vegetables and Bristol's Sunseed Organics.
"We have a great opportunity to source the best ingredients and create some fantastic food in a unique location," Fearnley-Whittingstall added. "Bristol is an exciting place to be part of and a great opportunity for everyone at River Cottage.”
Head chef Mark Stavrakakis will head up the team at the new restaurant which will feature a wood-fired oven.
Andrew Green, the River Cottage development chef, said new suppliers and breeders would also be discovered after the restaurant opens.
"As the Canteen opens, more and more small growers, breeders and producers will be discovered, hidden gems in amongst the wealth of Bristol countryside," he said.
"We never rest on our laurels and our door is always open to new suppliers that meet our ethos," he added.
Last month, River Cottage launched a professional cookery school for chefs.