WHEN your jaw begins to ache it lets you know that something is, genuinely funny.

Such was the effect Rob Brydon - as his earnest yet hapless alter ego, Keith Barrett - had during just under two hours with the transfer of the offbeat chat show to the stage.

Beginning as what our Welsh comic host described as a talk titled Making Divorce Work, fans of the tragic-comedy Marion and Geoff knew, broadly, what they were in for.

What they were not to know - or indeed was Brydon - were what tangents the live version, with its audience involvement, would take. It is hard to convey how Brydon, as Barrett, can wring quite so much humour from suicide statistics during his illustrated presentation opening.

Amid the almost non-stop laughter, there is some lacerating comedy in there - the kind that teeters on the verge of spite. It is edgy stuff but delivered so deftly that you are hardly aware quite how near the emotional knuckle it is.

This type of show is a far cry from traditional stand-up in format but Brydon does employ the skills of the stand-up.

The show ends with a couple invited on stage to be interviewed about their relationship. These kind of moments could be cringingly embarrassing.

Thanks to Brydon's control of the situation, however, it remains mainly mildly embarrassing for the couple but hilarious for the rest of us.