Joan Collins was last seen in the West End over ten years ago in a famously flopped revival of Private Lives. So there's no small dose of irony in her self-selected comeback vehicle, Ken Ludwig's backstage farce in which a production of the same Coward classic is spectacularly botched.

For that, and several other telling coincidences, Collins' choice is a brave one. She plays an over-the-hill actress fighting for a last-chance career break while desperately trying to ward off the ravages of time. Ring any bells? It can't be easy to send yourself up so, and for that matter, Collins doesn't make it look easy. Aside from being miscast and far too old for leading lady Charlotte Benson, Collins simply plays a bad actress extraordinarily badly. So much so that when, in the final scene, she wails in acknowledgement of the "limitations" of her talent, we can't help but nod in agreement.

Which is not to say that Collins is alone in shouldering blame here. Even with the most capable of stars, it's hard to see how Ludwig's script for Over the Moon could be funny. The nugget of the story is this: Charlotte and husband George (Frank Langella) are has-been board-tredders, currently in Buffalo, New York, on tour with their repertory company. An LA accident befallen Gary Cooper presents them with their golden opportunity to star in a Hollywood film. Legendary director Frank Capra is flying out to vet them in a performance of Private Lives. But an affair with an understudy and a bottle of whiskey stand in their way.

Though a modern play, Over the Moon is set in the 1950s and, humour-wise, seems stuck there, relying heavily on hackneyed ploys like dodgy hearing aids and split trousers. Ray Cooney's direction throws in plenty of extra hamminess, door slams and running around - to ill effect - and much of the timing seems off besides.

Castwise, beyond Collins, Langella has his moments, mainly when reciting Shakespeare rather than milking it as a tongue-hanging-out drunk. Cameron Blakely as daughter Roz's meteorologically inclined fiancé - who, luck would have it, gets so nervous he forgets his name - provides a few sunny spots. And, though somewhat cringe-inducing as Roz, Sarah Wateridge excels as a flustered Sibyl, valiantly trying to rescue the aforementioned Private Lives.

In fact, the scene containing the aborted Coward piece is by far the funniest of the play (perhaps because all the best lines are written by someone else?). But it is all-too brief. For value for ticket money, you'd be better off hiking over to the Albery (where Private Lives currently stars Alan Rickman and Lindsay Duncan) to see the genuine article.

- Terri Paddock