The Royal Festival Hall on the South Bank is to close for major refurbishment during the 2005-6 season.
The move follows the award of £15m from the National Lottery towards the £54m need for the relaunch plan. The Arts Council is to give £20m.
Chief executive of the South Bank Centre Michael Lynch said: "We plan to go out with a bang in 2005 and come back with an even bigger bang in 2006." The new plans are being drawn up under the direction of architect Rick Mather and will be finalised next spring.
(This story was updated and corrected on 14 October 2002)