The National Portrait Gallery will close for three years as part of a £35.5 million redevelopment project.
However, art enthusiasts will still be able to see the gallery's collection.
The gallery, near Trafalgar Square, wants to create a new main entrance to “bring back to life” its East Wing which has been closed to the public, and create a public forecourt.
It will loan hundreds of works from its collection during the period of redevelopment.
Visitors to London will have six months to enjoy the gallery in St Martin’s Place before it closes to the public from June 2020 until spring 2023 while “essential building works take place”.
A statement said: "In order to complete the project efficiently and to safeguard visitors, members of staff and the Collection, the Gallery in St Martin’s Place will temporarily close to the public from 29 June 2020 until spring 2023, while essential building works take place.
"During this time, we will continue to share our Collection with the nation as we embark on an ambitious programme of activities which will see hundreds of works travel across the UK through a series of partnerships and collaborations."
Detailing the changes, the statement added: "The project will see a transformed National Portrait Gallery with a comprehensive re-display of the Gallery’s Collection from the Tudors to now, combined with a significant refurbishment of the building, the creation of a new public spaces, a more welcoming visitor entrance and public forecourt and a new state of the art Learning Centre."
