How do you know that your musical TV show has become a global hit?
You're invited to the White House to perform the greatest hits from it, that's how. The cast and crew of Glee, the irresistible Fox series showing on E4 and Channel 4 over here, about an inspirational high-school teacher, Mr Schuester, who transforms the lives of a group of misfit pupils by starting a glee club for them, received just such an invitation in April. This was the moment when the First Family revealed themselves to be card-carrying fans of the series – or, to use the technical term, "Gleeks".
So, I ask Dante Di Loreto, the show's executive producer, what was it like to be introduced to the most powerful man on earth? "I was very, very fortunate to meet the President," Di Loreto beams. "I wish I could tell you something witty about the meeting. But the moment was so surreal, I simply became like a stammering nine-year-old!"
The residents of the White House clearly enjoyed the visit, though. "It was really fun watching Michelle Obama swing to "Don't Stop Believin'" and "Somebody to Love"," Di Loreto continues. "I could never have dreamt we'd end up in the White House."
The Obama family are simply four among millions of Glee aficionados (several dozen of whom are camped out in front of the central London hotel where the cast are staying when I arrive for my interviews with them.) After just one season, the show's popularity has turned the actors' lives upside down. Ensconced in a hotel suite under a canopy that has apparently been remaindered from Lawrence of Arabia, Matthew Morrison, who portrays the lovable Mr Schue, tells me that, "My anonymity has gone. I can't walk five feet without being stopped for a picture.
"But you have to embrace it. You work this hard and hope for something like this to come along, so you can't push it away when it happens. But I am buying a lot more hats now! I'm also walking around a lot in clear glasses – sunglasses make it look like you're trying too hard!"
Chris Colfer, who plays Kurt, the gay, fiercely theatrical pupil who is bullied by the jocks but manages to find acceptance through the glee club, has also had to cope with being mobbed wherever he goes. "People want to hold and comfort me because I'm always crying in the show. 'It's OK, Kurt,' they say, 'we love you'. I have to tell them, 'I'm fine, but thank you, anyway. I'm loving your sympathy!'"
Glee could so easily have turned out to be a lamentably tacky rip-off of High School Musical – all saccharine grins and even more saccharine messages about empowerment. Instead, it can be summed up by all those adjectives beginning with S: smart, sassy, savvy, sardonic. The TV series, which has already inspired stage shows in this country such as Don't Stop Believin' and Gleekfest, revolves around the characters reworking standard-issue pop songs into dazzlingly imaginative routines – Madonna's "Ray of Light" performed by a team of cheerleaders on stilts, anyone?
All the while, Mr Schue's well-meaning attempts to coach the glee club to victory in the regional singing competition are thwarted by his sworn enemy, the wondrously Machiavellian cheerleading coach, Sue Sylvester (played by Jane Lynch, who last week won a very well-deserved Emmy Award for her performance). The hilariously malevolent, garish-tracksuit-sporting ruler of the "Cheerios" is surely one of the best-ever TV baddies, prone to such utterances as: "As Madonna once said, I'm tough, I'm ambitious and if that makes me a bitch, that's what I am. Pretty sure she stole that line from Sue Sylvester. No, really. I said it first."
The show has succeeded in rehabilitating songs – such as the aforementioned "Don't Stop Believin'" – which once seemed irredeemably naff. Whole episodes have been devoted to singers such as Madonna and Lady Gaga, and artists are now elbowing each other out of the way in their eagerness to be featured on Glee (and, in the process, receive a massive boost to their record sales).
Keith Richards, of all people, is said to be a huge fan, something Di Loreto finds, "jaw-droppingly fantastic!" The forthcoming second series will dedicate an entire episode to Britney Spears, with Mr Schue shaving his hair off as a tribute to the troubled star. Glee has managed to make the cheesy credible.
The music is one of the principal reasons why the show, which is created by Ryan Murphy (Nip/Tuck), has struck such a chord with audiences. As in opera, it whips up the "perfect storm" of plot and passion. 31-year-old Morrison reckons that, "Music is what makes Glee so special. Music is an international language that we all speak. It's something everyone can associate with. Music gives the story a lift, it propels it to another level. Emotions are so heightened that there is nothing else to do but sing about it."
One of the other appeals of Glee, whose first season is released on DVD next week, is that it speaks to the inner loser who dwells within us all. 20-year-old Colfer comments that, "If you have any sort of outsider quality, then you'll identify with our show. And everyone has that quality, don't they? Everyone thinks, 'this is why I'm different'. Our show celebrates that individuality."
Amber Riley, 24, who portrays the ballsy Mercedes, agrees that, "People relate to the characters because they're outsiders. I say, 'embrace the loser within you!' You only become a loser when someone doesn't agree with what you're doing. But you know what? Who cares?"
Without ever ramming it down our throats, the show also promotes the idea of tolerance. Colfer says that, "It's about accepting people who are different." However, it seems that some have yet to take that message on board. Colfer continues that, "One kid wrote to me saying, 'we started a glee club at school and we get harassed for it every day. The teachers don't do anything about it. We went to the principal and he said, 'what do you expect if you copy a gay show?' Reading that made me want to put my cape on, fly out there and kick some ass!"
But Glee is not some po-faced preachathon – it exhibits a joyful willingness to send itself up. This trait is embodied by Sue, the teacher who delights in telling two of her charges: "You may be two of the stupidest teens I've ever encountered – and that's saying something. I once taught a cheerleading seminar to a young Sarah Palin."
"There's a bit of Sue in everyone," Di Loreto observes. "It says a lot about our humanity that we try not to let her out!" But she performs a vital function in Glee. "If the characters are ever taking themselves too seriously, Sue can turn up and tell them they're talentless idiots.
"One of the reasons the show has resonated is that we make fun of everybody. In our world, everyone has something that makes them special and unique, but also something we can make fun of. If we're the first ones to laugh at ourselves, then it's harder for someone else to do it."
One of the running gags in Glee concerns the rubbishness of Mr Schue's hair. At one point, Sue sneers at him: "You'll be adding revenge to the long list of things you're no good at, right next to being married, running a high-school glee club and finding a hairstyle that doesn't make you look like a lesbian. Love you like a sister!"
"How do I feel about the jokes about my hair?" Morrison asks. "It doesn't bother me, but I do feel I should be paid more money because my hair is another character! As people once asked for a 'Rachel from Friends haircut', perhaps they'll soon be asking for a 'Schuester'!"
One of the other achievements of Glee is to show that – contrary to the picture painted in some parts of the media – not all teenagers are hoodie-wearing, knife-wielding maniacs. "If a teenager is wandering around in a hoodie, that's because he's trying to fit in," Di Loreto reflects. "So if we can show teenagers a place to fit in, then we've done something positive. In our show, we don't question how gifted young people can be – that's a given."
The other positive upshot of the programme is that it is helping to renew interest in the performing arts at school. "Glee has put the spotlight on the arts in schools," says Di Loreto. "In the US, a lot of schools arts programmes really, really struggle. A lot of schools have been hit by tough financial times, and in that climate, the arts are the easiest thing to cut because they're viewed as the most frivolous.
"But a lot of new school choirs are now popping up and pupils are starting to mount their own productions. It's great if we're having that kind of influence. No one can tell me the world isn't a better place when people are singing and dancing!"
Finally, as the second season approaches, which guest-stars would the cast like to see appearing alongside them in Glee? "I want Julie Andrews to play Kurt's grandmother, and Madonna to play the ghost of Kurt's mother," asserts Colfer. "I'm heavily campaigning for that. I'd also love Queen Latifah to play Mercedes' mother and Aretha Franklin to play her grandmother."
Given Glee's popularity, that may well happen. Say a little prayer.
'Glee: the Complete First Season' is available on DVD now. The second series airs on E4 and Channel 4 soon