Seventy-nine people were injured after the ceiling collapsed at the Apollo Theatre on Shaftesbury Avenue last night, a London Ambulance Service spokesperson said.
"By the time the scene had been completely cleared, we had treated 79 patients," the spokesperson said.
Of those patients, nine were seriously injured, they added.
More top news
Weather set to stay cool and cloudy tomorrow
Europe's asylum, immigration and freedom of movement laws "wholly inadequate" to deal with arrival of hundreds of thousands of people.
A passenger who helped foil a suspected terror attack on a high-speed train in France is to appear on US show "Dancing With The Stars".