Police were called to a science fiction convention after an argument between two rival groups of fans.
Trouble flared at the fourth Norwich Sci-Fi and Film Convention at the University of East Anglia, organised by Norwich Star Wars Club.
Police were called after members of the rival Norwich Sci-Fi club arrived to get autographs from two Doctor Who actors at the event on Sunday.
Norfolk Police confirmed officers attended and spoke to both parties.
A spokesman said they had been called to reports of a man being assaulted at the convention.