The father-and-daughter-team, who earlier this year saw their three Michelin-star Arzak restaurant in San Sebastián come in at number eight in the rundown of the 50 best eateries in the world, will launch the venture in February 2013.
Ametsa with Arzak Instruction
"Ametsa means ‘dream’ in our language," Elena said, referring to the name of the London restaurant. "The dream of a kitchen beyond our frontiers, in the middle of London, in the heart of The Halkin hotel," she added.
Ametsa with Arzak Instruction will be run by a team of five from the Arzak restaurant in Spain including Juan Mari, Elena, Mikel Sorazu, Igor Zalakain and Xabier Gutierrez.
"It is a very exciting development for us. An Ametsa team led by Arzak Instruction's culinary advice," Juan Mari said.
The restaurant, with contemporary interiors inspired by Basque heritage designed by the firm AB Rogers, is expected to showcase the 'new Basque cuisine' which features in the original restaurant in San Sebastián.
Elena, who was named the World's Best Female Chef last year, had been rumoured to be making the move from Spain to the UK.
However COMO Hotels & Resorts has now confirmed a team of five, including Elena and Juan Mari, will actually take up the space at the Belgravia hotel vacated by David Thompson.
Nahm, which Thompson has run at The Halkin since 2000, will close before the end of the year. The Australian chef is now expected to concentrate on Nahm in another COMO venue in Bangkok which was itself a new entry in The World's 50 Best Restaurants in May.