Former N-Dubz singer Dappy has been found guilty of assaulting a man in a nightclub.
The 27-year-old, who was tried under his real name Dino Costas Contostavlos, denied attacking George Chittock in the early hours of February 27 during a public appearance at Chicago's nightclub in Chelmsford, Essex.
Dappy claimed he lashed out in self-defence.
But he was convicted by magistrates at Chelmsford Magistrates' Court and fined £800.
Chair of the bench Angela Tucker said the magistrates found Contostavlos was not under any physical threat at the time of the incident.
He held his head in his hands as the verdict was delivered.
Summing up the case, prosecutor Jacqueline Carey told the court: "It is no defence for anybody, celebrity or otherwise, to say 'I lashed out because he was rude to me'."
The court was read details of Contostavlos's criminal record, including a six-month suspended sentence for affray and assault in February 2012.
A trial last year heard he sparked a "mob-handed attack" when he spat at Grace Cochran and Serena Burton, who were both 19, at a filling station in Guildford, Surrey.
Mitigating, Mr Harrison said: "It was no doubt a regrettable incident but one that was over very quickly and left a person red-faced and very, very angry.
"He is a polarising figure who is clearly liked by a great many people but he is equally disliked by many others."
Referring to his client's ability to pay a fine or compensation, he said his client is well paid but his earnings are sporadic and he is currently awaiting a five-figure payment.
But he added that Contostavlos's finances were limited by a recent tax settlement.
As well as the fine, he was ordered to pay a victim surcharge of £80 and costs of £930.
Contostavlos did not comment as he left court but made a hand gesture to fans before climbing into a black Audi with tinted windows and driving away.