He spoke to another man after leaving an Edinburgh nightclub on Picardy Place at around 3am who then assaulted him.
The victim fell to the ground and was taken the Edinburgh Royal Infirmary for assessment.
He was later transferred to St John’s Hospital, Livingston for further treatment.
Officers are now investigating this incident and have appealed for more information.
The suspect is described as a white between 25 and 30 years old, with a medium build.
He is around 5ft 62” to 5ft 7” tall with short dark hair and a round face with stubble.
He was believed to be wearing a dark navy or black blazer, a checked shirt and dark denim jeans. He may have been in the same nightclub as the victim.
Detective Constable Joe Perkins said: “This was a violent assault, which has left the victim with a significant facial injury that will require further treatment.
“We would ask anyone who was in the area at the time of the attack, or who recognises the suspect description, to get in touch with us immediately.”
Those with information can contact Police on 101 or anonymously through Crimestoppers on 0800 555 111.