Facebook will expand its main UK offices by three quarters after it signed a new agreement with British Land, the owner of the central London development Regent's Place.
The deal will add a further 66,000 sq ft to the social network's existing 87,000 sq feet at the site, located north of Euston Road between Baker Street and Euston stations.
It follows Facebook's decision to withdraw from its 36,000 sq ft offices in Covent Garden. That site is now leased by King Digital, the maker of the smartphone game Candy Crush Saga.
Facebook's latest investment in Regent's Place solidifies the cluster of digital advertising companies that have been drawn north of Euston Road by multibillion-pound redevelopment.
Google is due to move into new headquarters near King's Cross next year and the advertising group Aegis has moved all its UK agencies to Regent's Place. The Government has also backed a 'Digital Catapult' centre in the area to host small and medium-sized businesses and foster collaboration.
Twitter abandoned its plans to move to Regent's Place, however.
James Danby of British Land said the new deal with Facebook was a "fantastic endorsement of the campus, and underlines their commitment to this location".
Facebook with occupy the fifth floor, floors nine to 16, and a ground floor events space in the building at 338 Euston Road. Its other offices at Regent's Place are in 10 Brock Street.
Last month the company expanded into its new 430,000 sq ft headquarters building in Palo Alto, California, designed by Frank Gehry and featuring the world's largest open plan office.