A murder suspect accused of kicking an Irishman to death in an alleyway blamed his lover for doing "most of the damage", a court heard.
Arry Green, 21, confessed to stamping on 37-year-old Michael Hunt after being told the victim had died in hospital, it is claimed.
He allegedly told his mother and stepfather: "I didn't mean to kill him. I can't believe it. I have killed him."
Green then claimed 24-year-old Fiona Nalty also kicked and stamped on Mr Hunt's head, jurors heard.
His stepfather, Philip Cumber, told the Old Bailey: "He told us that Fiona was the one who did most of the damage and was kicking him in the head.
"He said he hit Mick once in the face because Mick hit him on the nose. He stamped on him. Fiona was kicking and stamping on his head.
"He said he didn't mean to go that far and he was sorry. He was trembling, going hysterical when I broke the news to him. He nearly collapsed on the floor. I told him to hand himself in and tell the truth."
The court heard Green was having an affair with Nalty while he was in a relationship with a girl named Stacey.
"It was a secret," said Mr Cumber. "They were sleeping with each other. Arry would go to her house."
Mr Cumber, who was also a close friend of the victim, said he found out about Mr Hunt's death when they saw the police at the scene of the attack in Station Road, South Norwood, south London, on the morning of March 15 this year.
Jurors have heard Nalty and Green attacked Mr Hunt after the victim tried to chat Nalty up during a drunken night out.
Witness Amanda Crowther told the Old Bailey she was woken up by the sound of laughing in Station Road at around 3am.
She said: 'There was a man and a woman, they had their hands round each other's necks. It looked like they were messing about.
"Then they fell over and another bloke appeared. The girl got up and she looked like she was kicking him in the head.
'The other bloke tried to pull the man up and said, 'Come on mate, let's go down there and sort it out."'
Ms Crowther said the three of them then disappeared out of view and she went back to bed, only to hear the sound of a bin lid banging.
A 15-year-old boy has already told the court he heard Mr Hunt shouting "please stop" as he was being attacked.
The prosecution claim Nalty and Green then stripped off Mr Hunt's clothes before dumping his body in a skip.
Mr Hunt, originally from County Waterford in Ireland, was still alive when he was found the next morning but died later that day in hospital. He had suffered a fractured skull.
Nalty, of Fairdene Road, Coulsdon, Surrey, and Green, of Dinsdale Gardens, Norwood, both deny murder.
The trial continues.