The restaurant, cafe and catering company, which took over the contract to run catering at the British Museum in May, closed the restaurant in September to start work.
Softroom Architects have been appointed to 'radically renovate and redesign' the space which sits on a mezzanine level above the museum's Reading Room and directly beneath the Norman Foster-designed Great Court.
Major updates include the introduction of a central entrance, an open kitchen, a charcuterie counter and communal dining tables. Designers have also been tasked with creating three main dining areas - one overlooking the open kitchen, another with brasserie-style banquette seating for more private meals and private dining in the wings on either side of the restaurant.
A spokesperson for Benugo said the idea was to create a more welcoming environment for first-time customers.
"Great Court has now become more accessible and welcoming to visitors and museum goers, making it ideal for light bites and informal dining as well as appealing to the finer dining clientele," they said.
A new menu will be introduced by newly-appointed head chef Jason Wass with dishes designed to celebrate 'high quality, locally sourced food with a fresh focus on traditional European dishes'. The restaurant will open daily for lunch and afternoon tea, with an additional dinner service every Friday.
The new restaurant is one of the latest to be opened by Benugo. The group, which was founded in 1998 by Ben Warner and is operated by Guy Kellner, recently opened a restaurant in Soho in partnership with charity House of St Barnabas. It also runs restaurants and cafes at the V&A, the Natural History Museum, Ashmolean and Edinburgh Castle and recently won a £20m contract to run restaurants, cafes and kiosks at Regent's Park.
During its closure, the Great Court Restaurant was replaced by a pop-up restaurant called No.63 (named after the number of days the restaurant is closed for) at the museum's Gallery Café, where a selection of seasonal mains, salads and small plates inspired by food from around the world were served.