An "ambitious" £26.7 million restoration of Alexandra Palace is under way.
The work on the east wing of the grand venue in north London is due to be completed by the end of 2018.
Ally Pally, as it is often known, has been twice damaged by fire since it first opened to the public in 1875.
The Victorian theatre, which has been hidden for more than 80 years, will be restored to host plays, music and comedy gigs.
There will also be a public space in the venue's east court where exhibitions will be held to showcase the history of the palace.
Mayor of London Sadiq Khan said: "There is nowhere in London quite like Alexandra Palace.
"As well as being an architectural gem, surrounded by amazing parkland and spectacular views, it has an incredible tale to tell.
"Known as the birthplace of broadcast television, Ally Pally has survived two fires and has hosted a huge range of events for Londoners over the years, from Victorian theatre to the Brit Awards.
"This ambitious restoration project will take the Palace's story even further, breathing new life into one of the capital's most treasured cultural venues."
Alexandra Park and Palace Charitable Trust chairwoman Joanna Christophides, said: "For the first time in decades we are able to say with certainty that Alexandra Palace's future will be as glorious as its past. No longer a relic of another time but a testament to our own.
"The board is extremely grateful for the support of the Heritage Lottery Fund and Haringey Council.
"Without them and without the hard work and vision of the team here, Alexandra Park and Palace would fall into a state of irreversible decline."