It was inside the Bad Habits Bar in the Lower Pollet, and the incident itself happened just after 22:00.
A spokesperson said: “Police are looking for anyone who may have been present and witnessed the incident to please come forward and provide information to police.
“If you have any information regarding this incident you are asked to contact PC 51 HARRISON on 222 222 or to contact Crimestoppers anonymously on 0800 555 111.”