A host of stars attended a party to raise awareness of the plight of one of the world's oldest surviving grand music halls in east London.
About £3.5m is needed to save Wilton's
Celebrities including Hugh Grant and Helen Mirren attended to show support for Wilton's Music Hall.
The venue, built near Tower Bridge in 1858, is at risk of becoming unstable.
Earlier this year it was listed by the World Monuments Fund among 100 world cultural heritage sites currently under threat.
On its opening in 1858 Wilton's was described as the "Handsomest Room in Town" and hosted performances by the stars of the day.
But the building has been neglected over the years and is now a "semi-derelict" shell that could be unusable within three years, according to supporters.
In 2004 the Wilton's Music Hall Trust opened the building to the public, offering performances and guided tours. But millions of pounds are still needed to restore it.
Some funds have come from the Heritage Lottery Fund, and a steering committee was hoping guests at Wednesday night's party would help make up the rest.
Frances Mayhew, the music hall's director, said: "People love it as it is but, structurally, it's on its last legs and we need £3.5m.
"Saving Wilton's will be a lasting legacy. Somehow we've now got to make that happen."
Tower Hamlets councillor Denise Jones, a member of the Save Wilton's Committee, said: "It's the oldest music hall in this country and it's a beautiful, hidden building which is of great importance architecturally and historically.
"But it's also of great use to the community and the arts in London, and we want to make sure that that the building is preserved."