Charlotte and George Benson (Joan Collins and Frank Langella) are former Broadway stars reduced to playing in the provinces and to the gallery in 1950s America. Passed over by the movies and with TV snapping at their heels, they believe that their big break may have come when movie director Frank Capra flies in to catch a matinee performance.

All theatre demands a suspension of disbelief, but Ken Ludwig's backstage farce requires a suspension of disbelief so massive that it is as if an elephant had suddenly wandered on stage and blocked out the view.

You really do have to believe that there is no business like show business and that actors are endlessly fascinating and loveably mad. You must take it as given that the legendary film director Frank Capra really would want two near-septuagenarians to play Petruchio and Katharina in a movie version of The Taming of the Shrew, and that George would at the crucial moment get so rip-roaringly drunk he would not know if he was appearing in Private Lives or Cyrano de Bergerac. Then there is the Bensons' daughter, Roz, whose fiancÀ Howard (Cameron Blakely) is a weatherman who wanders around dressed up as General Patton and whom the Bensons mistake for Capra.

Ludwig's sentimental script and Ray Cooney's production - simultaneously laboured and wearisomely frenetic- do nothing to persuade that live theatre is not a dying art form, at least in this corner of the west end. It has become common to talk of thrilling nights in the theatre in terms of Viagra. This is pure cornball laced with Mogadon.

There is perhaps some irony in the fact that Ludwig's play with its heavy-handed message that old thespians must know when its time to stop playing Romeo and Juliet and hand over to the next generation, should be used as a vehicle for Collins and Langella. You have to admire Collins's determination to grow old disgracefully and refusal to act her age, but here she barely bothers to act at all, letting her famous legs do all the work. No matter because Langella acts quite enough for the two of them.

Strictly for those whose idea of theatre is Hello! magazine with dialogue.

Until January 12. Box office: 020-7928 7616.