According to Sussex Police, officers were called to 'a report of a disturbance' inside The Jungle Club in Chatsworth Road, Worthing, in the early hours of Sunday, October 31.
"Officers are investigating a subsequent report of an assault," a police spokesperson said.
"We were later able to obtain a statement from the victim and have regularly kept him informed of the progress made in the case so far.
"The investigation continues."
Anyone with information is asked to report it online, by calling 101 quoting the reference number 171 of 31/10/21.