Has it ever occurred to you that flippancy might cover a very real embarrassment?” That response from Matthew Macfadyen’s Elyot strikes at the surprisingly vulnerable heart of “Private Lives.” Noel Coward’s masterpiece is a balancing act between surface sophistication and true pain. But the delights of flippancy are only intermittently on offer in Richard Eyre’s effortful revival. It’s not just the headline casting of Kim Cattrall as Amanda that overbalances this production.

Coward’s construction is so perfectly symmetrical that its form shapes the comedy. Divorced couple Elyot and Amanda accidentally meet on adjoining balconies on the first night of their respective second honeymoons. They are then chased to their Parisian hideaway by their distraught spouses to face the music. It’s the theatrical equivalent of a perfectly matched mixed doubles final at Wimbledon. Or, rather, it should be.

Eyre’s revival is wise to the fact that the glamour of the dialogue and the deliciously bad behavior disguises very real emotions. But the subtext is emphasized so strongly that the surface text’s pleasures — and, therefore, many of its potential laughs — are diminished.

Some of this has to do with casting. The roles of the secondary spouses are key to the play in performance. Elyot has married Sibyl (Lisa Dillon), a beauty seven years younger. “You really are very sweet,” he tells her. Love, he now believes, is “something to smooth out your nerves when you’re tired.”

Here Sibyl’s naive sweetness rings false because the miscast Dillon, straining to act the character’s age of 23, appears a long way down the road to shrewish. Why, one wonders, has he married her? The question removes tension from the proceedings. That he dumps her for Amanda 40 minutes later isn’t daring; it’s a welcome, foregone conclusion.

The situation is better on the other side of designer Rob Howells’ peculiarly cramped and overcrowded balcony. Simon Paisley Day brings humanity and dignity to Amanda’s potentially pompousnew husband, Victor. Unlike the others, he embodies upper-class hauteur rather than demonstrating it. His blatantly honest, straight-up-and-down demeanor is a million miles from louche Elyot, so one immediately understands Amanda’s attraction to him.

Cattrall is as elegant and feline as could be hoped for. Indeed, swathed in nothing but a bath towel to begin with, she delivers half her lines with the winsome perplexed purr of Audrey Hepburn. The problems arise with the remainder of her vocal performance.

Like Wilde and Shakespeare, Coward’s lines have a natural rhythm that you meddle with at your peril. While that doesn’t mean affecting a Coward-esque voice, the delivery has to be easeful for the laughs to land. But it requires too much effort for Cattrall to iron out her North American inflections and accent, making her voice — and thus her performance — high-pitched and, on occasion, forced.

Macfadyen is an unusually weighty Elyot. But his unexpectedly baleful quality initially slows down the play’s pulse. He too warms up as the play progresses, but his rhythm only rarely seems in synch with Cattrall’s.

The play only truly comes to life in the scenes of physical comedy. Cattrall is funny when arch, bridling at Macfadyen’s amusingly sullen childishness. And she visibly relaxes in the well-staged marital fights in the Paris apartment. Yet in one of the funniest comedies in the language, it’s something of an indictment that the biggest laughs come from flying furnishings and a giant fish tank springing a leak.

The play’s writing is indestructible, but this most quixotic, effortlessly charming comedy runs on relaxed flair. U.K. theatergoers have been far from starved of “Private Lives” in the last 15 years. Cattrall’s presence may pull crowds, but compared with past couplings as blissful as Abigail Thaw and Simon Robson, or Lindsay Duncan and Alan Rickman, these two are simply working too hard.

Private Lives

Vaudeville Theater, London; 684 seats; £49.50 $74 top

  • Production: A Theater Royal Bath Prods., Duncan C. Weldon & Paul Elliott, Sonia Friedman Prods. presentation of a play in two acts by Noel Coward. Directed by Richard Eyre.
  • Crew: Sets and costumes, Rob Howell; lighting, David Howe; sound, Jason Barnes; musical arrangements, Matthew Scott; production stage manager, Sheena Linden. Opened, reviewed March 3, 2010. Running time: 2 HOURS, 10 MIN.
  • Cast: Amanda - Kim Cattrall Elyot - Matthew Macfadyen Victor - Simon Paisley Day Sybil - Lisa Dillon Louise - Caroline Lena Olsson
  • Music By: