Police were called to a sci-fi convention after trouble flared between rival fan clubs in Norfolk.
Tempers flared when members of the Norwich Sci-Fi club were refused entry to a convention organised by the Norwich Star Wars club at the University of East Anglia.
More than a dozen fans, many of whom were in fancy dress, were involved in the confrontation.
It is believed the confrontation started after a member of the Norwich Sci-Fi club approached Doctor Who actor Graham Cole for an autograph.
The rival groups had been involved in a long-running feud and the Norwich Sci-Fi group were accused of undermining the convention in comments made on social media.
Officers were called at around 2.30pm on Sunday to defuse the situation.
In a statement, Norfolk Police confirmed they had been called to reports of an assault but no further action would be taken.
Both groups subsequently told the Norfolk Evening News that they hoped to put their differences behind them.
More than 1,000 people attended the convention which had returned after a three-year absence.