Richard Eyre’s film “Stage Beauty” (R, 105 mins.) – based on Jeffrey Hatcher’s play “Compleat Female Stage Beauty” and adapted by him for the screen – inevitably recalls Keats’s line about beauty and truth. The setting is England during the reign of Charles II, and with the respective stage roles of men and women being redefined, truth and beauty are concepts in flux. The Elizabethan ban on women acting in plays was a curious exception to the practice in most of the rest of Europe; during Cromwell’s Commonwealth, of course, it didn’t matter, as there were no public theaters at all. But with the Restoration of 1660, the stage faced both the challenge of re-establishing itself and a shortage of young, trained male actors. Women were duly allowed to take on the female roles, and men barred from them.

The filmmakers would have us believe that like music’s castratos two centuries later, the men affected by this ban were rendered obsolete. In fact, that wasn’t the case, and in real life the hero of this picture, Ned Kynaston (Billy Crudup), went from triumphs in women’s parts to a respectable career playing his own sex – the natural evolution for comely lads who could only portray comely lasses for so long. But that wouldn’t make an interesting movie, and so Messrs. Eyre and Hatcher leave history to fussbudgets and try to have fun with the trope; they mostly succeed.

Like “Shakespeare in Love,” “Stage Beauty” uses the particulars of its time and place merely as set-up for a messy romance. And like that movie, this one allows filmmakers and audiences to feel superior about the same things – them for making the highbrow jokes, and us for laughing at them.

Kidding aside, knowing something about Restoration England is essential to appreciating just how glorious Rupert Everett is as Charles II. And get thee to a history book, if you’ve forgotten the role of Nell Gwyn (Zoe Tapper) in the monarch’s life. Likewise, Edward Fox’s deliciously puritanical Edward Hyde isn’t half as funny if you don’t know why he’s so dour. On the other hand, no book learning is needed to appreciate the comic timing of Richard Griffiths as Charles Sedley, or the spunk Claire Danes brings to Maria, Kynaston’s putative paramour.

The film ultimately belongs to Mr. Crudup, though, and he is quite a woman. Luckily, though, he’s also quite a man, which is the only thing that makes the slow-blooming romance with Maria plausible. Not that there’s any beating around the bush about elastic sexuality here. Kynaston apparently gave pleasure to both sexes, and they to him.

Those susceptible to clever dialogue and handsome production design may find greater virtues in this effort. But why diminish the real achievement? It’s called acting.