Wiltons Group, the business behind London institution Wiltons and its sister site Franco's, both in St James's, will open a third restaurant in the area in October.
The family restaurant group has managed Wiltons restaurant for more than 70 years on a site that stretches back to 1742.
Locket's, the group's first site to launch since 2005, will open on St James's Jermyn Street, offering a café and wine bar in the former home of the Economist magazine.
The site is named after the daughter of Wiltons Group co-owner Jamie Hambro. Locket told The Caterer
The 60-cover site will feature all-day food and drink, with a focus on a casual, high-quality breakfast, brunch and lunch, and will convert into a wine bar in the evening.
Sustainability will also be built into the site, with produce from sister restaurants used on the restaurant's daily changing menu.