Police say the murder happened at Castlereagh Place around 10 pm on Saturday night.
One line of enquiry is that the man was fatally stabbed following a fight in the area.
Two men, aged 21 and 25, and a 25-year-old woman have been arrested on suspicion of murder.
Detective Chief Inspector Alan Dickson, of the Major Investigation Team: “I appeal to anyone who was in the Castlereagh Place are around 10 pm last night and witnessed the incident or has any information to contact Detectives at Ladas Drive on the non-emergency number 101
“Or, if someone would prefer to provide information without giving their details, they can contact the independent charity crimestoppers on 0800 555 111.