Glee: All the right notes

It's not easy to predict whether a TV show will be a hit. For every Lost there's a The Nine, for every The Wire, a K-Ville and for every ER, a Three Rivers. So it's no surprise that when Fox first announced that their biggest new show of this year was Glee, a musical dramedy about a high school singing club created by Ryan Murphy, the twisted genius behind plastic surgery schlockfest Nip/Tuck and the brilliant but insane school drama Popular, most television insiders thought it would fail.

Firstly, no musical drama had succeeded since the kids from Fame back in the Eighties. We might live in a world where High School Musical has reeled in a generation of tweens while raking in the merchandising dollars from their doting parents, but the perceived wisdom, in the US at least, is that characters bursting into song might work on Broadway or for Disney but should never darken an adult TV screen. Whether it's Steven Bochco's still-shuddered-over Cop Rock or Viva Laughlin, the memorable-for-all-the-wrong-reasons remake of Peter Bowker's Blackpool, the accepted rule is that melody plus melodrama equals flop.

Add to that the fact that the early cancellation of innovative shows such as Pushing Daisies, Wonderfalls, Joan of Arcadia and Murphy's own Popular suggests that America is not generally happy with hyper-reality and whimsy, and it's easy to see why many TV execs felt that Glee – with its stylised school setting, larger-than-life characters and camp sensibility – was a risky proposition.

Would a large audience really be prepared to get behind the story of embattled yet optimistic Spanish teacher Will Schuester and his attempts to turn a ragged band of geeks, outcasts and conflicted jocks into a singing club like no other? The answer, perhaps surprisingly to those network execs, was yes. Glee debuted in the US to viewing figures of 10 million, in part because it premiered after the finale of American Idol, and has maintained a steady viewing average of 8.6 million.

So far, so solid, but what transformed Glee into the most talked about new drama of the year was the reaction from fans. Whether it was Twitter updates or Facebook clubs, iTunes downloads or tribute videos, the show's devoted army of "Gleeks" have turned an entertaining dramedy into a cultural phenomenon.

Suddenly Glee's cover versions – which have included clever takes on Amy Winehouse's "Rehab", Kanye West's "Gold Digger" and Neil Diamond's "Sweet Caroline" – were dominating the iTunes charts, an album featuring the best songs went straight to No. 1 in the US and the young, largely unknown cast were being asked to do everything from opening local shopping malls to singing the national anthem at Game Three of the World Series.

By the time Gap released a series of winter commercials clearly based on Glee's song mash-ups, Madonna agreed to allow her hits to be used later in the season and rumours (sin ce denied) began circulating that this year's X Factor winner will cover Journey's "Don't Stop Believin'", a song given a new lease of life by its inclusion in the Glee pilot, it was clear that this was more than just another high-school drama.

"Right after we aired the pilot in May, people started posting their own versions of the songs performed in the show online," says Dante Di Loreto, Glee's executive producer. "That's when we knew that we'd touched a chord. If we're doing it right then there's something for everyone. The relationships between the kids, the love stories and the friendships appeal to high-school kids, the more biting, acerbic comedy draws in the college students and parents watch it because they see the music they grew up with being reinvented. Different audiences see different things to love about it."

So why Glee and why now? The obvious answer is that in an era dominated by pop contests such as American Idol and The X Factor, audiences are increasingly willing to entertain the thought of a drama featuring songs, in addition to which the success of the High School Musical franchise has paved the way for Glee's more adult take on the genre. That said, comparisons between Disney's musical juggernaut and Glee have been swiftly (and occasionally angrily) dismissed by those involved with the Fox show. Most recently, Geoff Bywater, Glee's head of music, told Billboard that the wide range of music featured on the show (every genre from AOR to hip-hop, from R&B to show tunes has been touched on) made it a far more complex beast.

"Ryan Murphy's brain is iTunes," says Lea Michele, who plays would-be Broadway diva and school outcast Rachel Berry. "I've never met anyone with a musical vocabulary as incredible as his."

And, in truth, the best comparison is not to Disney's candy-coloured franchise but to Alexander Payne's witty indie hit Election, in which Chris Klein's easy-going jock and Matthew Broderick's earnest teacher found their lives derailed after coming up against Tracy Flick, a political force of nature played with considerable vim by Reece Witherspoon. Certainly there are times when Glee appears to nod to the film: Schuester's marriage, like that of Broderick's teacher, is in overtime and steadily approaching what promises to be a bitter end-game; Cory Monteith's sweet-natured quarterback, Finn, is, like Klein's character, undoubtedly nice but intent on redefining the word "dim", while Michele's Rachel Berry is a would-be Broadway diva and school outcast prone to Tracy Flick-isms such as "You might laugh because every time I sign my name I put a gold star after it, but it's a metaphor and metaphors are important. My gold star's a metaphor for me being a star" and "Being a part of something special makes you special, right?"

But despite those similarities – and for all the additional nods to Judd Apatow's groundbreaking high-school drama Freaks and Geeks – what makes Glee work is that in a time when most US shows appear to be about disturbed policemen or driven doctors with predictably complicated private lives, it's not afraid to march to its own musical beat. "The tone of the show is crucial [to its success]," admits Monteith. "It's so specifically written and it needs to be established properly for the jokes and the humour to work. He [Murphy] is the guy who basically came up with that tone and the direction for the show."

That uniqueness of tone is never more obvious than when Murphy, throwing away any pretence at reality, embraces the show's inherently camp nature and grants demented cheerleading coach Sue Sylvester, played with great gusto by Best in Show's Jane Lynch, the centre stage.

Clad in a variety of different-coloured tracksuits, her outrage at everything practically propelling her short blond hair upright, Sue is a repository of quickfire one-liners: "I don't trust a man with curly hair. I can't help picturing small birds laying sulphurous eggs in there, and I find it disgusting" is just one passing sally to the hapless Will, and Di Loreto admits that her character comes close to stealing the show: "Jane makes Sue a delicious villain," he says. "She's somebody who we all love to hate because she says things that we might think at times but we would never say."

That said, ultimately it's not Sue's one-liners, great though they can be, which make the show so compelling. "We're prepared to admit that occasionally terrible people do terrific things and terrific people can do terrible things," Di Loreto says, adding that one of the show's strengths lies in the fact that behind the stereotypes – the flamboyant gay boy, the popular jock bully, the spoilt, god-worshipping cheerleader, the bolshie black girl – lies a group of characters who are more complicated than they might initially appear. "Nobody is completely good or completely bad. Things change as the season progresses and I think certain characters will surprise you."

Monteith agrees: "The thing about Glee is that it's quirky and upbeat and bright but I think that what really makes you care about these characters is that there's a real heart to the show," he says. "It's sweet, it's not saccharine, it's not cheesy, but it is true."

Monteith's comments might sound on the cheesy side themselves, but he's right that it is Glee's heart that has made the show a hit. In a time of recession and job loss, when each news bulletin seems more depressing than the last and the world appears an increasingly grey place to live in, Glee's optimism, its belief that underdogs may yet conquer the world (or at least make it to the sectional singing heats) and its determination to prove that no matter how bad things might get, there's nothing that an over-the-top AOR cover can't solve, mark it out as that rare thing: a genuinely joyful television experience that wears both its snark and its heart on its sleeve. Or as the indomitable Sue Sylvester memorably stated: "Every time I try to destroy that [Glee] club, it comes back stronger than some sexually ambiguous horror movie villain." Now that's an endorsement worth having.

The pilot episode of 'Glee' will be shown on 15 December (E4, 9pm), with the rest of the series airing from January

Glee playlist: The club's best covers

Journey: 'Don't Stop Believin''

Think it's a boring AOR ballad, think again, as the 'Glee' cast transform an overplayed rock song into one of the year's most uplifting moments by stripping the power chords away.

Amy Winehouse: 'Rehab'

Glee's rivals at Carmel High School turned this into a choral masterpiece complete with some very flashy dance moves.

Bon Jovi & Usher: 'It's My Life/ Confessions Pt 2'

Glee's favourite trick is the mash-up, when two songs are merged into one, and none succeeded better than this reworking of Usher with Bon Jovi featuring a star turn from the wheelchair-bound Artie Abrams.

Kanye West: 'Gold Digger'

West's paean to girls who like cash, as covered by earnest teacher Will Schuester, should be one of the year's most cringeworthy moments; yet thanks to a great intro from cast member Amber Riley, it somehow isn't.

Neil Diamond: 'Sweet Caroline'

While many of Glee's covers are all-singing, all-dancing affairs, this one works because it takes Diamond's famous song back to the basics, turning it into "a personal tribute to a musical Jewish icon" from one guy and his guitar.

Beyonce: 'Single Ladies'

Yes, it's the dance move of the year, but Glee's decision to have it performed by the McKinley High football team in an attempt to put off their opposition works almost despite itself.

Best of '09: What was your favourite TV programme of 2009? We want to hear about your most memorable cultural moments of the year. In the comments form below or at independent.co.uk/bestof09 or via email to arts@independent.co.uk, nominate your favourite - in film, music, theatre, comedy, dance or visual arts - with a brief explanation as to why it tops your list and we'll print a selection in The Independent Readers' Review of 2009.