There are no laboured political messages in Cats, only the horny pleasures of watching the Rum Tum Tugger hip-thrust his way through increasingly surreal dance routines. “The dancing, the costumes, the music, the concept, the story – it’s so engaging,” gushes 37-year-old mathematician Will Gosnell, from Amherst, Massachusetts. He saw Cats 23 times on Broadway. “It pulls you in, and you get hypnotised by the whole show.” Such is his love for Cats, Gosnell has written three cat-related songs, which he has uploaded to his YouTube channel. What’s the Cat Gonna Do?, Mister Man the Kitty Wears Pink Sweaters, and Horton the Extraordinary Cat are all inspired by Gosnell’s affinity for the feline species, as well as the oeuvre of Lloyd Webber.

Cats’ elaborate costumes also help. “It gives the fans an opportunity to feel like they’re part of the show, by getting little groups of friends together and knitting leg warmers and swapping wigs and going to fan conventions,” Dooley says. Castronovo has Munkustrap, Skimbleshanks and Gus costumes, which he wears to performances. Once, he dressed as Munkustrap during the matinee performance of the 2012 revival at the Gateway Playhouse in Long Island. “I had a front-row seat, and at the end of the show I’m literally nose-to-nose with the real Munkustrap,” he rhapsodises. “He gives me this look like: ‘Get lost – you’re not one of us. We don’t want you here.’” What about the confusion over whether the cats are human-sized? “To start putting the cats in bedrooms and streets and bars is really brave,” Thomas says, explaining that issues of scale aren’t a factor in the stage show, as the cats don’t leave the junkyard set. “I think they are supposed to be cat-sized cats, because in the last show of the trailer, where they’re in the square, you can see their proportions.” Cats fans are the most engaged of any in musical-theatre history. But why do they keep returning to the Jellicle Ball, all these years on? “To escape,” says the Australian film-maker Mark Dooley. His documentary Repeat Attenders tells the story of the musical-theatre superfans who see the same shows over and over again. “For two-and-a-half hours, you’re in another world, and nothing else – not what’s happening in your real life – matters. You can be surrounded, and entertained, and feel joyful, for that time.” The stage show also stands out because of its strong element of audience participation. “You’re really enmeshed in it,” McLamore says. “You’re not sitting 100ft away – you’re really involved in the action and the scale of things.” The film critic Hannah Woodhead, 26, saw the Cats film at least 40 times before she caught the touring version as a child at the Sheffield Lyceum. Sitting in the aisle was as clever a decision as Mr Mistoffelees himself would have made. “The cats run through the audience and purr and nuzzle your leg. For me, as a child it was like: is theatre always like this? My mind was absolutely blown.”