Naturally 7 @ Barbican Centre

Surprisingly, my husband manages to fit in a job other than me. He works for AEG, proud owner of the O2 and other impressively echoey sports and music venues around the world. Pre-husbandisation, he invited his lovely colleague in Berlin, Markus, to attend our wedding with his equally lovely wife and son Alexa and Timon. Bear with me. I'll get to the ridiculously talented accapella guys in a minute.

Alexa and Timon couldn't make it, so instead they sent a best-wishes video from Berlin for us to watch on the day, featuring a whole host of AEG colleagues too. None of them could pronounce our name. It was very moving. The room got a bit dusty. And then, because they were playing the O2 World Berlin and Markus had collared them in the lift, seven super-energetic black dudes in co-ordinated bad-boy outfits popped up to say congratulations.

They were Naturally 7. It took me a while to realise, jumping and squealing like a girl who just happened to find some old Facebook shares in her handbag at their show at the Barbican last night, that they were them. I was too busy having fun watching them coax a Barbican audience  - majority middle class, middle aged and fed up from wandering for hours trying to find the bloody place - to full ovating, yelling, booty-busting splendour in a blistering old-school feel-good feast of a gig.

Naturally 7 produce their own R&B songs, as well as covers by everyone from Phil Collins to DMX to Simon & Garfunkel, using nothing but their voices. Every instrument, DJ effect and sample loop is created vocally. Sure, it's a stunt, but when its executed this well it never gets dull. You can keep your retro 50s barbershop boys and soulful 60s acousticians. These guys have classic technique and musicality galore but they also have a bouncy, heartfelt playfulness and enthusiasm that has nothing to do with being cool and everything to do with giving your audience a damn good time.

So a belated thanks, boys, for the marital blessing - I had no idea you were this awesome. Everyone else, catch them when you can. Wear something that soaks up sweat and a big stupid 2012-style grin.