Rain man, Apollo Theatre, London

You'd get a poor idea of the possibilities of theatre as an art form from the movie star Josh Hartnett's dull, undistinguished performance. It's his co-star, Adam Godley, who shows you what real acting is in this production, slickly and skilfully directed by Terry Johnson.

Godley plays Raymond Babbitt, the "developmentally disabled" and institutionalised autistic savant who can memorise the telephone directory, but has no friends in it that he could ring up. Enter his long-lost brother, Charlie (Hartnett), who is peeved at their late father's will, which leaves $12m to the crank and nothing to Charlie, the financially strapped car dealer.

Hartnett's inexperience is at its most damaging in the silences that punctuate and accelerate the tentative, growing rapport between the siblings. These silences are nerveless absences of speech, rather than the charged moment of intensity that they should be. And when Hartnett speaks, he can't always wrap his mouth crisply enough around the fast-talking dialogue.

Godley, though, is an anguishing joy. His Raymond has all the premature elderliness of the permanently precocious. He looks like a mix of floppy toy monkey and a dogmatic stickler-for-routine old lady. He comes across as a being infinitely marooned in a vast loneliness that it would be harrowing to plumb. Ideally, you would want from Hartnett some suggestion that Charlie, though on the ball and in full use of his balls, has complementary emotional difficulties. That, though, would require a balance of talents less lopsided than those arranged for us by the esteemed producers.

To 20 December (0870 040 0046). A version of this review has already run in some editions of the paper