If music is infectious, then the Festival Theatre should have been quarantined last night because there was a serious outbreak of rock and roll mania.
Symptoms included shaking limbs, standing ovations and for one unwitting lady egged on by the cast, some hip gyrations which would have made Elvis Presley look like a fence pole.
By the end, the audience was shouting out for more – but how did it happen?
The show gets its name and premise from a night when rock royalty Johnny Cash, Elvis, Jerry Lee Lewis and Carl Perkins got together for a one-off jamming session at Sun Records, the independent label which made them famous.
Being a jukebox musical, it could easily slip into tribute act territory – but the actors playing the titular quartet were talented enough to live up to their characters. They were all musicians of the highest calibre, particularly Martin Kaye as Lewis, whose skill verged on the ridiculous when he played sat on top of the piano with his back to the keys. And who needs choreography when you can watch a man play a guitar behind his head and while stood on a bass?
Be in no doubt: this show is all about the music. The storyline is just there to link the songs together, and despite a poignant moment where the cast recreate a real photograph taken on the night, the show faltered whenever it tried to get too serious or deep - particularly in exposition-crammed monologues delivered by an oddly-cast Martin Kemp as the record producer Sam Phillips.
Oddly, it was at its best when it dispensed with plot completely during the encore, which revelled in the unadulterated joy and energy of the music.
It’s no mean feat to get the Festival Theatre crowd dancing like teenagers at a concert, but that is exactly what happened.
Afterwards, I overheard one man say to a stranger ‘that was quite a night’ – and for what it’s worth, I’m inclined to agree.
Until November 11.