The cast of Matilda and their audience had to evacuate after the incident at the school.
Headmaster Ewan Murray said: “It was incredible to see the calm and professional way in which the young cast coped when sadly, a malicious activation of the emergency alert system interrupted the performance on Tuesday evening, causing the building to be evacuated. This matter has been referred to Police Scotland.
“Despite this, in true theatrical fashion, the show went on!”