A man has been left with serious facial injuries after he was attacked outside a city nightclub.
The incident happened around 3am on Sunday directly outside the Jam House in Queen Street.
A 51-year-old was waiting outside the premises for his partner when he was headbutted by another man who had been in the venue.
The suspect is described as white, in his 50s, around 6ft tall with a stocky build and shaved head. He was wearing a dark striped shirt and dark trousers.
Detective Constable Carole Sneddon said: “The victim was assaulted without any warning and sustained a serious facial injury. We are now conducting various lines of inquiry to trace the male responsible.
“Anyone who witnessed the assault or who has information relevant to this investigation is asked to contact police immediately.”
Those with information can contact Police Scotland on 101 or alternatively, the charity Crimestoppers on 0800 555 111.