The 100-cover restaurant will be based in a 19th century drawing room in the New Wing of the West End arts and culture venue – a space which has been closed to the public for 150 years.
Gyngell, who was previously head chef at the Michelin-starred Petersham Nurseries Café, will create changing daily seasonal lunch and dinner menus comprised of eight starters, eight main dishes and five desserts.
Opening mains will include grilled langoustine with seaweed butter, Fiore di Latte, pickled pumpkin, speck and sage oil and fillet of beef with brown butter, anchovy and wild greens, while desserts will include buttermilk cream with rye shortbread and damson ice cream and hazelnut tart with warm chocolate sauce.
A separate area, The Salon, will serve seasonal ice creams, sandwiches and Bierin – an espresso and chocolate drink from Turin.
Gyngell’s long-term business partner, Marie Jackson, will act as director of operations, while the front-of-house team will be led by general manager Sofia Franc, formerly of River Café and Petersham Nurseries, and head maître d' Sarah Flyckt, who previously worked at The Delaunay and The Wolseley.
Head sommelier Frank Embleton, who will join Spring from The Clove Club, has worked with wine consultant Jack Lewens to design a wine list dominated by French and Italian wines, alongside some English varieties.
The drawing room, which has large windows and high ceilings, will be decorated simply, with natural oak flooring and a central atrium garden created by landscape designer Jinny Blom.
“I’m thrilled to be opening a restaurant in the very centre of London that will remain deeply in tune with the land and the seasons,” said Gyngell.
“My cooking has always been driven by a respect for beautiful ingredients, and I feel truly privileged that my first solo venture will allow me to share that pleasure with others every day in this historic setting. I hope this wonderful room will become the scene of many memorable, convivial meals.”
BigHospitality reported last September that Gyngell was tipped to take over one of the two 4,500 sq ft units in the West Wing, which was used as offices by the Inland Revenue until last year.
Spring is the first restaurant to be confirmed at the Wing, and will be the fourth on-site eatery at Somerset House, which also plays host to outposts from Fernandez & Wells and Tom Aikens.
“We are delighted that Skye has chosen Somerset House as the site for her first restaurant in London after Petersham Nurseries," said Jonathan Reekie, director of Somerset House Trust.
“Somerset House is a creative hub in the heart of the world’s culture capital which invites you to try something new and a little out of the ordinary, and the same will be true at Spring.”
Gyngell trained under Anne Willan at La Varenne in Paris and worked at The Dorchester and The French House before helping set up Petersham Nurseries Café at Richmond garden centre in 2004.
She was head chef at the café for eight years, during which time it was awarded a Michelin star, before leaving in 2012 to pursue her dream of opening her own restaurant.
Spring will open at Somerset House, Lancaster Place, London, WC2R 1LA on 14 October 2014.