A 37-year-old window cleaner from County Down pleaded guilty to murdering a man in North Antrim in October 2016.
Richard Hugh Jackie Dalzell - of Whinpark in Newtownards - had previously denied murdering Mark Anthony Lamont in Coleraine.
He was due to go on trial on on Thursday 8 March.
When the charge was put before him in Belfast Crown Court, he replied "Guilty."
Mr Justice Colton told the defendant: "Mr Dalzell, you have pleaded guilty to murder and I must impose upon you the sentence of life imprisonment."
The judge said he would set the tariff for how long Dalzell would spend in prison without parole at a hearing on Friday 13 April.
No details were given in court today about the circumstances surrounding the murder.