A long-time Dolly Parton impersonator stopped the show when members of the audience got onto the stage and disrupted the finale.
Musical extravaganza Country Superstars – which sees Dolly Parton impersonator Sarah Jayne, singer Andy Crust and others perform classics from Kenny Rogers, Patsy Cline, Johnny Cash, Shania Twain and John Denver – had already seen a rowdy group threaten theatre staff and members of the audience at The Woodville in Gravesend.
Singer Sarah Jayne said she was initially unaware of any problem, which happened at the back of the auditorium. She said: "At the beginning, everybody was in a good mood. When Dolly came out everybody was screaming and made an abrupt cheer.
"I just thought it was quite regular, the amount of cheering and screaming, but as the show went on some people were being louder than usual, a bit more than you would expect them to.
"It was not until the interval we knew (what had happened). We were on stage but we were not aware of it as it was at the back. We did not know what was going on. There was not any difference, from my point of view as a performer.
"We carried on as usual and we continued with the performance. It was not until the end of the show when they came to the front of the stage. They were not violent towards us."
But Sarah Jayne said two audience members then decided to get up onto the stage and interrupt the finale numbers, Islands in the Stream and 9 to 5.
She said she asked them to leave and stopped the band so that the theatre staff could help remove them.
Police were called to the venue on Saturday, February 12 when about 15 people became "extremely aggressive".
They used threatening behaviour and language towards others in the audience as well as staff, and now face being banned from the venue.
Their actions were condemned as 'unacceptable' by Gravesham council, which runs the theatre.
Cabinet member for community and leisure Shane Mochrie-Cox said: "We are extremely angry and upset at the totally unacceptable behaviour which spoilt the show for the rest of the audience and the performers, and which caused considerable distress and upset for members of the public and theatre staff alike.
"I would like to apologise to all those who had their evening ruined and we will be offering full refunds to anyone who requests them.
"We had no reason to believe that this particular show would be the cause of any problems."
The group was allowed to remain in the auditorium having returned to their seats early in the show, but after the police left their behaviour deteriorated further.
Melanie Norris, director of community and leisure at the council, added: "This was an incredibly difficult situation for our staff to manage in the face of threats and extremely aggressive and anti-social behaviour."
Sarah Jayne, who grew up in Medway, added: "I have never had this happen before in this way. We were really upset that people were upset on the night. We are very lucky that this is rare.
"The theatre is very happy to have us back again and just try to put some measures in place. It was just a small group of people. It is a bit of a shame, really.
"We are coming back next year and are really excited."
The council is studying CCTV of the incidents and anyone identified as having taken part will be banned from The Woodville.