It was in a B-movie cinema in a small New Zealand town that the alluring mixture of horror and glamrock took hold on Rocky Horror's creator, Richard O'Brien.

His resulting creation sparked to life in the tiny Royal Court Theatre in London in 1973, almost overnight turning into a monster hit, and inspiring its cult following. It is now celebrating its 25th anniversary.

The musical, which was subsequently made in to the film The Rocky Horror Picture Show, has songs inspired by the 1950s, but heavily influenced by the sexual revolution of the 1960s and the Glam rock excess of the 1970s.

O'Brien played the role of hunchbacked manservant Riff Raff in the 1975 film adaptation.

Click here for an interview with Richard O'Brien

Richard O'Brien says Rocky is a modern fairytale

The plot involves a young and square American couple - Brad and Janet - who accidentally stumble into a strange and terrifying world of alien transvestites and polymorphous sexuality. As the show unfolds the two innocents begin to enjoy themselves.

The show has inspired a whole Rocky Horror subculture where audience members dress as their favourite characters and call out responses to each well-known line. They sing along and dance to songs such as The Time Warp and Dammit Janet, and even bring props which include party hats and water pistols to use at appropriate moments in the show. The founder of the Rocky Horror Picture Show fan club is reputed to have seen the film over 1000 times.

Jason Donovan as Frank 'n' Furter

According to Lisa Wood, fan and promoter of The Rocky Horror Show, there are currently 30 productions of the musical on in the US and it is never off the stage in Japan. It is has also played this year in South Africa, Austria and Germany.

The latest production on tour in Britain stars Jason Donovan as the outrageous transvestite Dr Frank 'n' Furter. The role was made famous by the British actor Tim Curry, who starred in the original stage version and the film.

The show opens in the Richmond Theatre, Surrey, on May 18. On the anniversary night Mr O'Brien intends to make a guest appearance on stage at the end of the show and encourage the audience to sing Happy Birthday to Rocky.