ASBESTOS was found at Theatre Royal Wakefield.
The discovery was made under the stage during an inspection last month and that area has now been sealed off.
But the theatre remains open as normal and work to remove the asbestos will begin in January next year.
Executive director Murray Edwards said: “The main thing is we did not anticipate it but we found it, we dealt with it, and we have made it safe.
“We were obviously very concerned to make this discovery and acted immediately to make the area safe.”
Mr Edwards said the theatre did not anticipate anything coming up in the inspection but stressed that the building was perfectly safe for performers, staff and public.
He added: “We are working closely with Wakefield Council and following agreement with environmental health officers, the under-stage area has been sealed off.
“Air tests in the surrounding areas have confirmed there is no contamination outside the affected space and these tests will be carried out regularly through the run of our annual programme.
“Once the pantomime has closed, the removal process will start prior to the start of the spring season in late January 2013.”