The project will see the construction of a new flytower, as well as creating extra dressing rooms and office space, with the aim of "ensuring the long-term viability of the venue to accommodate large-scale, self-produced and touring productions".
Located at the corner of Shaftesbury Avenue and High Holborn, the Shaftesbury Theatre was the last theatre to be built on Shaftesbury Avenue, and opened as New Princes Theatre in 1911. It underwent an internal refurbishment in 2006, and has also seen the exterior elevations of the theatre restored to the original Edwardian features.
The flytower was strengthened in 2002 to increase capacity and in recent years has seen further temporary adaptations to accommodate larger shows. The proposed extension, on the eastern boundary of the building facing Grape Street, will increase its height and loading capacity.
The west face of the extension will incorporate dressing rooms and office accommodation, increasing and consolidating the theatre's support spaces which are currently housed in several locations across the site.
James Williams, chief executive of the Shaftesbury Theatre, said: "Whilst maintaining the grace and beauty of the Shaftesbury we will now have a contemporary addition that will enhance the facilities of the theatre giving us the capacity to accommodate the increasing demands of productions. We are thrilled with the benefits that this will bring to our customers, producers and actors visiting and working at the Shaftesbury."
The proposals, which have been made by Bennetts Associates Architects, employ distinctive cor-ten steel cladding, which responds to brick and terracotta in both the existing theatre facades and the adjacent King Edward’s Mansions.
Simon Erridge, director at Bennetts Associates, added: "The extension to the flytower at the Shaftesbury Theatre is an exciting and important addition to the prominent Grade II* listed theatre and will ensure the future of the theatre to host large-scale productions. We look forward to working to deliver a design which not only transforms the theatre experience but creates a contemporary architectural addition to this important West End site."
The Shaftesbury Theatre has hosted many productions in recent years including Fame, Hairspray, Flashdance and Rock of Ages. Burn the Floor runs until 1 September 2013. New Tim Rice musical From Here to Eternity premieres there in the autumn.