The pledge was secured following a successful bid from Brighton & Hove City Council and Brighton Dome & Brighton Festival, the joint custodians of the Royal Pavilion Estate.
The renovation will improve the sustainability, working conditions and facilities at the Brighton Dome’s three venues: the Concert Hall, the Corn Exchange and the Studio Theatre.
Proposed plans include new seating and infrastructure, and a viewing gallery and audience circulation space at the Corn Exchange, major improvements to the Studio Theatre’s ground floor bar and café, additional offices and a service tunnel linking between the three venues.
Andrew Comben, chief executive, Brighton Dome & Brighton Festival, said: "We are delighted and proud to be awarded this funding from Arts Council England.
"As the first phase of the broader vision for the Royal Pavilion Estate, the development plans for Brighton Dome Corn Exchange and the Studio Theatre form a major part of our goal to be one of Europe’s leading arts festivals and a year-round international destination for artists and audiences."