The Rocky Horror Show creator on musical's 50th anniversary as it returns to Yorkshire

“It really was just a bit of fun. It is a juvenille piece of nonsense if you think about it,” he says from the home in New Zealand he shares with his third wife some 40 years his junior. "It is strange, the whole thing is bemusing.”

O’Brien had contemplating giving up acting after he was dropped from playing Herod in Jesus Christ Superstar. “They paid me off,” he says. “I had £300 in my pocket, had my first baby and no job. I was really thinking whether I should give it all up and get a proper job. I got a job singing and telling jokes. When I was asked to perform at an EMI party, I wrote a song Science Fiction/Double Feature

"In the New Year I wondered whether it might serve as as prologue to the germ of an idea that I had for a musical. I shared that thought with Jim Sharman who had directed Jesus Christ Superstar. Jim liked the concept and away we went.” And the result was the Rocky Horror Show.

"1972-73 was a moment of change. Glamrock and overt sexuality was around, gay people were coming out and there was a ‘buzz’ in the air. There are certain parts of the world where we are a little bit more free to be ourselves. London is certainly one of them. Back in the Seventies you had gay bars, but now you don’t need to because if you walk into most bars in London there will be a gay man behind the bar. That is rather nice.”

The Rocky Horror Show follows two wholesome American sweethearts, Brad and Janet, who stumble upon a spooky tumbledown mansion where they are relieved of their inhibitions by Frank-N-Furter, the sweet transvestite from transsexual Transylvania.

He doesn’t like to be drawn into whether the Rocky Horror Show is more relevant today than when it was first performed to an audience of just 63 at the Royal Court in 1973, but he does think it has contributed to the discussion of gender and sexuality.

“That wasn’t intended but I’m grateful it’s helped other people feel less isolated or lonely. Being transgender is a nightmare for many people. I’m very lucky that I’m in showbiz where I can be this eccentric person and therefore it’s allowed. If I were a primary school teacher maybe that wouldn’t be the case.”

O’Brien has referred to himself at ‘third gender’ being 70 per cent male and 30 per cent female and he admits that Rocky did help him with his own sexuality.

"It must have been, to some extent, cathartic but I have always gone my own way and played the cards that I was dealt at birth the best way that I can.”

What was meant to have a three week run at a fringe event with nothing more than a black box and a pretend movie screen as scenery, ended up being, transferred multiple times, and within 18 months had been turned into the ultimate cult movie starring O’Brien in his roll as hunchbaked Time Warp-dancing Riff-Raff, Tim Curry as Frank and Susan Sarandon as Janet. “We were all allowed to play our own parts. It was all kind of lovely, none of it was planned it was a lovely journey.” The film is still shown in cinemas around the world nearly 50 years after its premiere, making it the longest running theatrical release in cinema history.

The audiences for both the movie and the musical are as much apart of the show as the actors, pitching up week after week in wigs, corsets, fishnets and slap. “The actors are free to win the song and win the audience. It’s not an opera they don’t have to sing the perfect notes they can speak the lines if they, they just need to win the song and the audience.”

So why does he think Rocky is still a success 50 years on? “It is simply a musical comedy and as long as it rocks, and the audience are laughing what more could you wish for? It's very inclusive, it's very easy to watch. It's not rocket science as far as narrative is concerned - Brad and Janet are a couple that we kind of recognise as Adam and Eve or Romeo and Juliet, like a stereotypical couple - we can all relate to them. It is also a fairy tale which allows us to feel comfortable with its rites of passage storyline. A retelling of Hansel and Gretel if you like, with Frankfurter standing in for the wicked witch. The innocent rather naughty fun of it draws not only a ‘theatre’ crowd but also people who want a fun evening and a guaranteed return on the investment of their ticket price.”

He says his favourite part of the show is still the end. “The noise at the end of Rocky is wonderful – it is empowering and exhilarating at the same time it is quite joyous. Rocky never fails to deliver. Each performance lifts the heart and the nightly laughter and roars of approval leave the whole cast with a sense of wellbeing and accomplishment that you rarely get from any other shows. To be celebrating 50 years is beyond my wildest expectations - from the humble beginnings back in 1973 at the Royal Court Theatre in London. The fact that The Rocky Horror show continues to delight audiences as it tours the UK fifty years on is simply thrilling. The Rocky Horror Show is one of Britain’s most performed and beloved musicals of all time.”

How different does he think his life might have been without Rocky? “I have no idea but, I would have had a good life because I am made that way. My journey has been a different one than others. I guess some people have a game plan. I would imagine they’re rather humourless. Most of us get an opportunity and we wing it. Luck plays an awfully big part in our lives. You should never underestimate that. I am the luckiest person on the planet.”

The 50th Anniversary production of The Rocky Horror Show will run at the Leeds Grand Theatre from Tuesday until Saturday and at New Theatre, Hull from October 9-14.vwww.rockyhorror.co.uk