A four-star boutique hotel is being planned for the Grade II listed Bromley Town Hall.
The site is set to include a hotel plus wedding and conference facilities, as well as a restaurant, after the London borough council entered into a conditional agreement with developers Cathedral Group.
The historic, early-20th century building's original features will be restored, including the still-standing staircase, entrance vestibule and council chamber. There is also an extension on the building dating back to 1939, which contains an art deco staircase and wood panelling.
Listed building consent applications should come through later on this year.
Councillor Stephen Carr, leader of the council, said: "We are committed to ensuring that Bromley maintains its competitive position, building on our rich heritage, as well as stimulating new and quality developments. The Town Hall site is a fantastic opportunity to provide the town with a high class facility."
Richard Upton, Cathedral Group chief executive, said that the aim was to create a destination hotel with high-quality conference and event facilities to meet demand.
He added: "Given the ambition and scale of regeneration taking place in Bromley, We believe this kind of development will be significant addition to the town centre."
The borough is also planning other developments including a new cinema.