The landmark office at 338 Euston Road provides 112,000 sq ft of office space over 17 storeys, and will be comprehensively refurbished when tenants Hachette and BT vacate in May.
Facebook will occupy the fifth floor of the building, as well as floors 9-16 and a ground floor events space, totalling 66,000 sq ft.
This space is in addition to the 87,000 sq ft that Facebook already occupy at Regent’s Place, following the company’s decision to relocate their UK headquarters to 10 Brock Street in 2013.
The office refit is expected to be completed next year.