Steven Doherty has sold the Punch Bowl gastropub in the Lake District to the owners of the Drunken Duck in nearby Ambleside for about £600,000.
Paul Spencer, joint owner of the Drunken Duck, said the Punch Bowl would close for three to four months to add eight bedrooms and refurbish the restaurant and bar area.
Spencer added that the gastropub would continue to serve the same high quality food in the restaurant, but would develop a traditional British food menu in the bar.
Doherty, who won three Michelin stars alongside Albert Roux at London's Le Gavroche in the 1980s, will be concentrating on his role running the in-store restaurant of Windermere-based domestic kitchen equipment business Lakeland.
The Windermere store has a restaurant seating capacity of 100 and is regularly serving 700 covers a day with a weekly turnover of £3,000.
Doherty said: "It's the next big thing to happen in catering. People come into a Lakeland shop to buy quality kitchen equipment and it's a natural progression that they want to eat quality food in-store."