On Saturday afternoon, an expected horde of more than 500 people dressed as the walking undead will dance to Michael Jackson's 1982 hit Thriller. The dance will be filmed, as it is hoped enough people will turn up to break the current world record for the most simultaneous dancers, currently about 4,500.

The event has been organised by Flashmob Northampton, who have arranged similar impromptu flashmobs at other locations in the town in the past.

Organiser Jof Davies said: "This is my final flashmob so I wanted to do something quite big to end it, and when I heard this terrible news about Michael Jackson I thought it would be a fitting tribute to him.

"We have 4,500 members on the Facebook group and about 500 confirmed guests. The official Michael Jackson fan club is publicising it, so fingers crossed we should have more than 5,000 people."

A number of practice sessions are being held to brush up people's moonwalk in advance of the event and dance leaders will be at the front of the crowd so dancers can follow the moves.

Mr Davies said: "The feedback has been amazingly positive. Everybody seems really happy about it." The event takes place in the Market Square at 2.15pm.