A spotlight blew up during a performance at The Playhouse in Norwich, scattering glass over the audience.
Nobody was injured during the incident, which caused 'minor disruption' to the evening.
A member of the audience, who did not want to be named said: 'One of the theatre spotlights blew up, it made quite a bang and scattered glass on the heads of the audience, it also sparked. The show stopped and they turned on the house lights.
'Part of the lamp was hanging from the ceiling and swinging. The performers re-started while the staff picked up glass and swept it up.
'The staff moved some of the audience out of their seats and then the orchestra had their interval early.
'No-one was injured and the staff were brilliant. During the interval they cleared the majority of the audience out and produced a ladder.
'One of the techies went up and lowered the broken light on a rope. After that, the show went on as normal but with lots of jokes about 'light entertainment'.'
The bulb blew on Friday evening during a performance by the Pasedina Roof Orchestra.
Assistant theatre manager Andrew Ramsbottom said: 'They called an early interval so we could make sure everyone in the audience was OK. Thankfully, there was minor disruption and no-one was injured.'
He said it was the first time this had happened during his many years at the Playhouse.
He added that the theatre took the health and safety of its customers very seriously, and the technical team would meet on Monday to examine what happened.
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