LONDON — A sequel to musical comedy classic “The Rocky Horror Picture Show” has hit the London stage some 30 years after it was first penned.

“Shock Treatment” was written by “Rocky Horror” creator Richard O’Brien and made into a film in 1981 but it did not have the success of the original musical, which has built up a big international cult following over the decades.

Following “Rocky Horror” characters Brad and Janet into a world of television media, “Shock Treatment” is now being staged for the first time at a London theater with the go-ahead from O’Brien and music composer Richard Hartley.

Directed by Benji Sperring and adapted for the stage by Tom Crowley, the production has cut the film’s cast from around 20 roles to seven and has reworked the script.

“The film was a bit of a mess really but we always thought we had some good songs and when Benji approached us about putting it on stage, I thought why not?” Hartley told Reuters.

“It’s been completely re-imagined by Tom Crowley and it’s become a show for today.”

Sperring said he had pursued O’Brien for nearly 10 years to get the rights to stage the show. He finally agreed but on the condition that it be put on at a small venue — just as “Rocky Horror” was when it made its theatrical debut in 1973.

Both the “Rocky Horror” stage musical and film have become hugely popular, with audiences dressing up and interacting with the characters and fan clubs staging theme parties.

“We’ve got no idea if the audience will get up and get involved or if they’re going to sit back and be passive or if it’s going to be a very active piece,” Sperring said.

“The actors are prepped as much as they can be and they’re aware that they’re just having fun. Richard O’Brien very early on said ‘Let fun be your guide and as long as you’re having fun, the show will be alright’.”

The show features London stage actress Julie Atherton as Janet and Australian actor Mark Little as TV executive Farley Flavors.

“Shock Treatment” runs until June 6 at the north London King’s Head Theater.