Film director Oliver Parker is fond of controversial fiddling with established stage classics. In 1995 he reinvented William Shakespeare's "Othello" as a relationship-intensive, semi-erotic psychological thriller. In 1999 he took liberties with Oscar Wilde's "An Ideal Husband," adding scenes and whole subplots with amusing but contentious results.

"The Importance of Being Earnest" is Parker's second stab at going Wilde, and while he once again retains the playwright's savory wit, this time out his plot-tweaking attempts to break out of the drawing room are often distractingly blunt and obvious. Chase scenes, tattooed buttocks and flashbacks of an out-of-wedlock pregnancy -- all new elements dictated by Parker -- are hardly the caliber or the character of any Victorian writer, even one as droll and roguish as Oscar Wilde.

However, a talented cast with keen comic timing helps assuage many of the movie's misfires. Colin Firth ("Bridget Jones's Diary") is nebbish perfection as Jack Worthington, a mannerly turn-of-the-Century country gentleman who invents a wayward brother named Earnest as an excuse for frequent trips to London to sow wild oats. In town he adapts the name Earnest himself and romances the prim but rebellious and beautiful Gwendolen Fairfax (Frances O'Connor), whose stuffy, high society mother (Judi Dench) is resolutely disapproving of all her daughter's suitors.

While on one trip to London, Jack's best friend (and Gwendolen's cousin) the puckish ne'er-do-well Algie Moncreef (Rupert Everett) assumes the identity of the nonexistent Earnest Worthington and travels to Jack's estate in order to put the moves on Cecily Cadrew (Reese Witherspoon), Jack's young ward who has often fantasized about meeting and falling in love with her caretaker's knavish "brother."

When Jack returns early from London -- with a determined Gwendolen hot on his heels and her peevish mother not far behind -- false identities are blown, hearts are tied in knots and all hell breaks humorously loose at the Worthington estate. Oscar Wilde's melodiously tart dialogue sounds like comedy magic rolling off the tongues of Colin Firth and Judi Dench -- who is dressed in upper-crust costumes so extravagant that she's funny without even opening her mouth. She looks as if a flock of peacocks exploded in her closet.

Best known for ditzy blonde roles in distinctly American movies (e.g. "Legally Blonde"), Witherspoon distinguishes herself as the hopelessly romantic Cecily, pulling off a precise English accent and giving her rather cartoonishly byronic character an inquisitive and skeptical edge.

The other main characters don't fare quite as well. Algie is too vaguely drawn by Rupert Everett, who once seemed the ideal Oscar Wilde actor in his devilish, smug, sharp-tongued aristocrat role in "An Ideal Husband." And while Frances O'Connor is a wonderful actress who brings a lot of pluck to the role of Gwendolen, she's just a tad too old at 32 to be credible as a girl who gets engaged to Jack/Earnest, only to be scolded by her mother, "When you are engaged, I or your father will inform you of the fact!"

For the most part Wilde's droll whimsy helps "Being Earnest" overcome its weaknesses and Parker's creative interference, leaving only the play's inherent absurdities (Cecily and Gwendolen are both bent on marrying men named Earnest, for example) as obstacles to enjoying the film. But tongue-in-cheek preposterousness has always been part of Wilde's charm, so my advice is to forgive all the film's problems and simply have fun.