Former N-Dubz singer Dappy told police he slapped a man in self-defence as he lived in constant fear he might be stabbed, a court has heard.
The 27-year-old, who appears on the court list under his real name Dino Costas Contostavlos, is accused of attacking George Chittock in the early hours of February 27.
He denies assault by beating and is standing trial at Chelmsford Magistrates' Court.
Prosecutor Jacqueline Carey told the court the incident happened after Contostavlos carried out a "meet and greet" at Chicago's in Chelmsford, Essex.
In a police statement read to the court, the performer said he had been "cut" in an incident four or five years earlier at a nightclub in Nottingham.
Asked if he feared he was going to be stabbed on the night of the incident, he added: "Yeah of course, I'm always concerned about that.
"I was scared someone was going to put a hole in me.
"I have had to deal all my life with people trying to cut me and taking cheap shots."
He added he had been attacked on three previous occasions in the 12 months leading up to the incident.
He claimed Mr Chittock had abused him three times over the course of the night, including insulting his dead father.
"He looked like he was going to do something," Contostavlos said. "It was self-defence, I did not want to get hit."
Contostavlos arrived at court in a black Audi with blacked-out windows.
Escorted by a minder, he wore a black jacket, white shirt and black tie. His friend, comedian Jim Davidson, also attended in a show of moral support.
At two points in the hearing chair of the bench Angela Tucker asked Contostavlos and those who escorted him not to mutter while witnesses were giving evidence.
Ms Carey told the court the pair were in a smoking area along with Contostavlos's minder and two of the club's own door staff at about 2am when he was seen to slap Mr Chittock.
CCTV footage of the alleged attack was played to the court.
The black-and-white footage, which lasts about 10 seconds, showed Contostavlos "surrounded by security" when he turned and "slapped" Mr Chittock, Ms Carey said.
Ms Carey said: "When the defendant lashed out, he was not under any threat or any perceived threat of violence."
Jon Harrison, defending, said that earlier in the evening Mr Chittock told Contostavlos: "Dappy, you're a mug, I'm going to knock you out."
Mr Chittock replied: "Incorrect."
He suggested that on a second occasion, Mr Chittock was ejected from a VIP area after saying to the performer: "Do you remember me, you pussy?"
Mr Chittock agreed he had been ejected from the area as the star had his photo taken with fans but said it was the result of a misunderstanding and he did not say anything abusive.
Asked whether he had said to Contostavlos "go suck your dead dad" seconds before he was slapped, Mr Chittock said: "I would not say that, I have close family members who have died and that is not right."
Mr Harrison asked whether he knew that Contostavlos's father was dead.
Mr Chittock said: "I don't know anything about his family.
"I'm not a fan of him, I don't care what goes on in his life.
"His life and my life are separate."
In response to suggestions he had deliberately intimidated Contostavlos, Mr Chittock added: "I was not in his face. I was not in his personal area. He turned around to strike me."
James Armstrong, a security worker at Chicago's, said he escorted Contostavlos and his entourage of 10 friends and a close protection officer into the nightclub after he arrived at midnight.
During the evening, Contostavlos drank half a bottle of Grey Goose vodka and some Jack Daniels, Mr Armstrong said.
"I could tell later in the night he was very intoxicated," he said.
"I thought it was a bit peculiar someone of his stature was drinking from the bottle.
"That bottle remained with him most of the night."
Contostavlos finished in second place to Davidson on reality show Celebrity Big Brother a month before the alleged incident.
Outside court, Davidson said: "Dappy is a good friend of mine, we became close on Big Brother.
"I don't know what's happened in this case but I'm just here to show him my support."
Contostavlos, of St Albans, Hertfordshire, is on unconditional bail.
Giving evidence, Contostavlos, who gave his profession as performing artist, said he was feeling "energetic and alive" on the night of the incident.
He insisted he did not have a "drinking habit", adding: "I was functional enough to go and do an amazing show so I certainly wasn't drunk."
Contostavlos said he would not be able to drink half a bottle of vodka without falling over.
Telling the court he was about 5ft 4ins and weighed eight stone, he added: "Look at me I couldn't down half a bottle of vodka in the space of 20 minutes of me going on stage."
He said that when he arrived at the club he heard somebody shouting "mug, mug, mug".
He added that the "same boy" caused trouble later in the night when he refused to have his picture taken with him.
"When he reached me he had this cold look at me as if to say 'I'm not here because I like you'," Contostavlos added.
"I got intimidated so I stood back.
"Why would I want my picture taken with him?
"He didn't like me so he wanted to cause harm to me in some sort of way.
"I was like 'Come on bro'."