Glee Live, Radio City Music Hall, New York

When the makers of Glee announced that they were taking their show on the road for an all-singing and dancing extravaganza featuring some of the hit drama's best-loved covers, it was hard not to feel slightly underwhelmed.

After all, the greatest appeal of Glee is not so much those covers, entertaining as they can be, as it is the sharp dialogue, which neatly undercuts an occasional tendency towards saccharine. Surely without that clever, deflating script Glee is little more than High School Musical with a dash of Broadway thrown in?

Add to that questions over some of the cast's singing ability when away from the safety of the mixing studio and it was all too easy to see this as just another X Factor-style cash-in.

In the event such cynicism was wildly misplaced. From the moment that the curtains at Radio City Music Hall pull back to reveal a taped message from Matthew Morrison's laid-back Will Schuester and Jane Lynch's acerbic Sue Sylvester, the former telling us to support the kids even as the latter suggests we will need vomit bags, it's clear that a great deal of thought has gone into preserving Glee's irreverent tone.

It's also clear that this isn't going to be the sort of evening that starts slowly and builds to a climax. If Glee the television show can feel almost giddily over the top, Glee the live event not only celebrates that feeling, it ramps it up to eleven.

Thus the cast kick off with their best-known cover, Journey's "Don't Stop Believin'", and have hardly drawn breath before we're treated to a series of solo performances, from a show-stopping "Don't Rain on My Parade" by Lea Michele (the show's uptight diva Rachel) to a moving rendition of Christina Aguilera's "Beautiful" by the big-voiced Amber Riley (who plays bolshy Mercedes). And we're only four songs in when Mark Salling, aka resident bad boy Puck, treats us to "Sweet Caroline".

Other highlights include a cover of the musical Wicked's "Defying Gravity" by Michele and Chris Colfer (the flamboyant Kurt), a jazzed-up take on Amy Winehouse's "Rehab" by rival show choir Vocal Adrenaline and a version of Lady Gaga's "Bad Romance" in which Naya Rivera, aka bitchy Santana, steps into the spotlight and makes it her own.

It's not all perfect, of course. Michele, who made her name on Broadway in Spring Awakening, is in a separate class – a situation that becomes even more obvious when she sings Lionel Richie's "Hello" with Jonathan Groff, who starred with her in that show and who now plays Rachel's boyfriend and rival on Glee.

Indeed Groff's strong vocals only serve to remind us that the Glee boys are on the whole weaker than the girls. Colfer, who has a lovely pure tone, does well while Salling has enough sex appeal to compensate for any shortcomings, but Kevin McHale (Artie) and Cory Monteith (Finn) are both occasionally overwhelmed by the arrangements, their vocals not quite strong enough to stand out.

Not that the over-excited audience cares. It's hard not to get swept up with them. It might not be the most polished show in New York right now, but it's certainly the most joyous and entertaining.