Just before the lights dimmed, a pre-recorded announcement informed: ‘Please note that all of tonight’s music is played and sung live on stage.’ And thank goodness this was broadcast since it isn’t immediately obvious that the show’s cast are versatile, accomplished musicians.

This isn’t meant to discredit the production but actually sing its praises, because so natural, so immediately ‘real’ are the performances of this multi-talented cast I actually forgot I was in a theatre it felt that ‘alive...

Instead, as if hypnotised by a click of Derren Brown’s fingers, I found myself immersed in a world of beehive hairstyles and teenage boys desperate to be the next James Dean.

Written by Laurence Marks and Maurice Gran, the team behind Goodnight Sweetheart and Shine On Harvey Moon, Dreamboats and Petticoats boasts an irrepressible glee.

The story itself is flimsy – two young musicians compete to win a national song writing competition.

But what there is of the script is smart, knowing and funny. And the cast are enormously likeable and believable.

However, where this production really scores is with the staging of its musical numbers (and unlike most musicals, here you get a classic song every three or four minutes), topped off with a no-holds barred concert at show’s end.

And yes, every number is played and sung live. Impressively.

I simply cannot think of a single thing I would change – it’s simple, wonderful, happy, and feel-good.

It does what it says on the tin, and for me the real buzz kicked in when I recognised that the show’s lynchpin character, church club organiser Phil, is none other than Terry Winstanley, the ex-lorry driver from last year’s X-Factor.

And boy what a revelation he is. Brilliant. Like Bob Hoskins but with a big dash of Sinatra.

Totally dreamy.