Timing, King's Head, London

Ex-partners make a habit of running into one another in comic plays and films. In Private Lives, Noël Coward arranges for his former spouses to meet on adjoining hotel balconies in the South of France, where they have both just embarked on their second honeymoons. In Timing, the very funny debut play by the actor and impressionist Alistair McGowan, there's a fresh, fertile twist to the formula. Julian and Amanda are voice-over artists who, after seven years of strained estrangement, wind up in the same tiny London recording studio where they are disarmed to find that they've have been booked to appear together in a radio advert.

In a 30-second commercial for a SatNav system, they are to impersonate a bickering couple who have lost their way in the Cotswolds. They can certainly bring something of their own, Stanislavski-fashion, to that scenario, which has been penned by Wes and Dino, "the Gervais and Merchant" of the genre (or so they like to think). But, as professional pressures and personal tensions become entangled, will life be able to imitate "art" and get the pair back on track?

It's a clever idea compounded by the notion of periodically presenting us with two plays in one. The "creatives" sit on one side of the studio's soundproofed glass wall; perched in their little booth, the actors are on the other. We can hear what is happening in both areas even when they can't listen to one another. As it flicks between these sealed-off settings and counterpoints the characters' overlapping preoccupations, the play requires expert comic timing and it gets that here from the crack cast of Tamara Harvey's quick-witted, enjoyably buoyant production.

Full of piquant, anthropological knowingness, the play pulls you into the absurdity of a world where a half-minute ad can be combed through for back-story and motivation, as though it were a masterpiece by Ibsen, and where a requested 10-second cut can result in major squabbles about the placement of "beats" and what is "fuckin' pivotal" to its "basic gender politics". In the long wait for "client clearance", Peter Hamilton Dyer's hard-drinking Scots Dino lapses into professional self-disgust for having helped to create a society where kids will kill one another for an iPod. Cut off in their booth, Edward Baker-Duly and Georgia Mackenzie (vocally delicious as the former couple) look back in rancour to an abortion that he was too busy doing voice-overs for Airwick to support her through.

The issue of parenthood, the priorities it imposes, and the pains of being excluded from it, haunt both sides of the glass wall. The play is not without the odd creak of contrivance, but Louise Ford, lofty in her Stella McCartney heels, is bliss as the semi-vacant, obliviously privileged 23-year-old producer, who thinks that the problem of mortality has been solved by YouTube. They can have my client-clearance instantly.

To 8 November (0844 412 2953)