Jessica Swayle's joyful play works like a dream on so many levels. When Charles II cries "Down with austerity," he may of course be referring to Oliver Cromwell's notorious era of puritanism, but the cheeky grin tilted at the audience confirms that this is a very modern joke. And when Gemma Arterton's Nell Gwynn - the prostitute who became Britain's first famous actress - cracks any one of her filthy one-liners, she too is playing to today's crowd.

The action is set in late 1660s Reformation London. But Christopher Luscombe's production has not a hint of po-faced costume drama about it. Its sheer fun lies in its ability to combine a saucy, winking knowingness with some pretty serious observations about how women are depicted in the theatre. And not just then, now too.

"They've disgraced our trade. Ruined our art. They've put a woman on the stage'' protests a male actor whose job involves donning a wig and linen breasts to play female roles. He is no match at all for Arterton's Nell who pushes the theatre company's writer in residence John Dryden into giving her some decent roles to play.

"You can write for a real woman now," she tells him. "We're as knotty and tangly as you are, and yet how do you write for us? 'Oh Romeo, Romeo, lend me your dagger so I can kill myself!'"

So the real story in this joyful show is that the chance to perform fleshed out female characters here is not only taken by Gwynn, but by Arterton who displays a total command.

It's a little unfashionable, or downright dodgy, for a male reviewer to dwell on a female actor's beauty. The actors don't like their performance to be reduced to mere looks, and no reviewer wants to come across as a lech.

But Arterton is stunning. She has the kind of beauty that would usually suggest inaccessibility were it not attached here to a girl-next-door, down-to-earth charm and, most winningly of all, a talent for comedy that saves Gwynn's bawdiness from coming across as just Barbara Windsor-vulgar. This is one of the best plays and one of the best performances in the West End.