Size, as they say, matters. That idea is not lost on Sonia Friedman and her raft of U.K. producers on “Legally Blonde,” who have put the show in a smallish house more accustomed to plays than lavish tuners. Their financial gamble pays off big time thanks to a heap of reasons, chief among them being casting. This guilty pleasure of a show remains precision-engineered candy-floss, but as Elle, pint-sized knockout Sheridan Smith gives it heart and helium levels of happiness.

The 1,156-seat Savoy has only two-thirds the capacity of Broadway’s Palace. Although that puts pressure on early recoupment, the far more compact physical space supplies significant gains.

A taller, less deep auditorium and the covering of the silvered art-deco walls on either side of the proscenium conspire to bring audiences’ attention closer to the action. And with a more square than widescreen-shaped stage, there’s a satisfying degree of extra focus on director-choreographer Jerry Mitchell’s perfectly drilled antics.

Any concerns about such profoundly American material looking uneasy in the U.K. are batted away by the dizzyingly well-driven pace of the opening sequence. Like “Hairspray” — the show that serves as this tuner’s model — the mostly musical exposition of character and situation is so slick you barely have time to breathe. By the time you do, the show has already drawn you in.

Part of the speed at which Heather Hach’s tight book goes about its “Clueless”-goes-to-law-school business is due to a level of characterization that’s not exactly Proustian. But the warmth engendered by the performers ensures it never totally descends into mere cartoon.

Perfectly chiseled Duncan James, more pop-singer than actor, finds little to do with pompous love interest Warner Huntington III, but since being stupidly handsome is the sole job requirement, that’s hardly his fault. Elsewhere, however, there are surprising levels of wit at work.

An unrecognizable, blonde-wigged Jill Halfpenny does a nice line in deadpan depressed dimwit as trailer-trash beautician Paulette Buonufonte, while TV favorite Peter Davison nails the law professor. His regular nice-guy persona gives the plot switch where he angles for sexual favors from Elle a startling kick.

There’s even more quietly impressive work from Alex Gaumond as Emmett, the poor, bright guy who finally gets the girl. Resisting the temptation to push the “cute nerd” button, he never overplays his hand. Instead he allows the attraction to stem and grow from the sweetness of his singing voice and the ease of his playing.

He’s helped considerably by the fact that the woman he falls for is so touchingly sincere. Smith is a smart dancer and has a good, if not stunning, singing voice. But as countless TV roles have shown, she’s a real actor.

Elle dreams of a bright and shiny life, a hope-filled demeanor Smith delivers in spades. It’s infectious and immensely winning because she deploys razor-sharp comic timing without ever sacrificing properly developed emotion. She’s deliciously knowing but never arch. Even when surrounded by silliness, she has an uncanny knack of making you lose sight of the performer, to empathize directly with the character’s hopes and dreams.

While the original Broadway production cost around $16 million, the London figure is closer to $4 million. With running costs of less than half what they were in New York, this transfer looks set to thrive as long as Smith wants to stick around and steal hearts.

Legally Blonde

Savoy Theater, London; 1,158 seats; £62.50 $102 top

  • Production: A Sonia Friedman Prods., Robert G. Bartner, Ambassador Theater Group, Bud Martin, Adam Zotovich, Jamie Hendry Prods., Act Prods. presentation, in association with MGM On Stage, Darcie Denkert and Dean Stolber, of a musical in two acts with music and lyrics by Laurence O'Keefe and Neil Benjamin, book by Heather Hach, based on the novel by Amanda Brown and the Metro-Goldwyn-Mayer film. Directed and choreographed by Jerry Mitchell. Musical direction, Matthew Brind.
  • Crew: Sets, David Rockwell; costumes, Gregg Barnes; lighting, Kenneth Posner, Paul Miller; sound, Acme Sound Partners; wigs and hair, Richard Mawbey; orchestrations Christopher Jahnke; arrangements, O'Keefe, James Sampliner; production stage manager, Jo Miles. Opened Jan. 13, 2010. Reviewed Jan. 12. Running time: 2 HOURS, 25 MIN.
  • Cast: Elle Woods - Sheridan Smith Emmett Forrest - Alex Gaumond Warner Huntington III - Duncan James Professor Callahan - Peter Davison Paulette Buonufonte - Jill Halfpenny Brooke Wyndham, Shandi - Aoife Mulholland Vivienne Kingston - Caroline Keiff Serena - Susan McFadden Margot - Amy Lennox Pilar - Ibinabo Jack Veronica, Enid - Suzie McAdam Grandmaster Chad, Kyle, Dewey - Chris Ellis-Stanton