The 26-year-old, whose real name is Costadinos Contostavlos, is accused of attacking the man in the early hours of February 27 after he made an appearance at Chicago's nightclub in Chelmsford, Essex.
He pleaded not guilty at Chelmsford Magistrates' Court to one count of assault by beating.
Contostavlos, of St Albans, Hertfordshire, stood in the dock in a white shirt, black trousers and black trainers as the charge was read to him.
He was granted unconditional bail and will stand trial at Chelmsford Magistrates' Court on June 18.
The former N-Dubz singer finished in second place on reality show Celebrity Big Brother in January.