That troubles both Richard D'Oyly Carte (RON COOK), the impresario who oversees both the theater and its troupe -- including Gilbert and Sullivan -- as well as his assistant, Helen Lenoir (WENDY NOTTINGHAM). For not only are box office returns dwindling, but Sullivan, the composer of the duo, feels that his work has become stagnant and wants to move on to more serious musical pieces.

Unfortunately for him, he and Gilbert, the lyricist, are contractually obligated to deliver another opera for the Savoy, and he isn't motivated by his collaborator's latest effort. Things appear to be at an impasse until Gilbert's wife, Kitty (LESLEY MANVILLE), drags him to a Japanese exhibition. Suddenly inspired by a different culture, Gilbert begins to write "The Mikado," an opera that similarly sparks the creative juices in Sullivan.

Soon the two begin working with the Savoy's regular cast that includes veteran performer, Richard "Dickey" Temple (TIMOTHY SPALL) and lead actress Lenora Braham (SHIRLEY HENDERSON), as well as Durward Lely (KEVIN McKIDD), Jessie Bond (DOROTHY ATKINSON), George Grossmith (MARTIN SAVAGE) and Rutland Barrington (VINCENT FRANKLIN), as well as Mr. Seymour (NICHOLAS WOODESON), the stage manager, and John D'Auban (ANDY SERKIS), their choreographer.

As the days count down toward their opening and with encouragement from Kitty and Fanny Ronalds (ELEANOR DAVID), Sullivan's mistress, the excited, nervous and worn out duo, along with their cast and crew, continue rehearsing in hopes that their latest opera is a creative and financial hit.

Of course, the most famous theater-related person was probably William Shakespeare, but notwithstanding the fiction of "Shakespeare in Love," relatively little is known about the man outside the minds and work of some theatrical scholars. While not as recognized as the Bard, two Englishmen from the late 1800s, Sir William Schwenck Gilbert and Sir Arthur Seymour Sullivan - best known simply as Gilbert and Sullivan -- certainly made a similarly deep impression on the theater world with their comic operas such as "H.M.S. Pinafore" and the high school favorite, "Pirates of Penzance."

Yet, despite their well-known body of work that often parodied Italian operas, English Elizabethan madrigals and introduced a new musical setting known as the "patter song" (where singers would rapidly deliver long lines of lyrics), little is known of the two theatrical giants. That is, until now. Although it's uncertain whether writer/director Mike Leigh's comic homage to the masters will catch on with the public as well as the Gwyneth Paltrow/Joseph Fiennes vehicle about the Bard, it's certainly about as delightful and as much fun to behold.

A serious departure in style from Leigh's previous works including the extremely static, but well performed "Secrets & Lies," this film is sweeping in scope. With gorgeous cinematography (courtesy of cinematographer Dick Pope - "Swept From the Sea," "Secrets & Lies") costumes (by Lindy Hemming - "Little Voice," "Four Weddings and a Funeral") and production design (by Eve Stewart - "Career Girls") accompanying Leigh's more fluid visual sense, they collectively combine to create some glorious period eye candy.

Beyond the film's impressive visual sense, however, it's the performances by the two leads embodying the theater legends -- along with Leigh's strong script and dialogue -- that allow the film to really take flight. Somewhat amusingly reminiscent of a more serious version of Bernard Fox's Dr. Bombay character on TV's "Bewitched," Jim Broadbent ("The Borrowers," "Little Voice") is perfect as the headstrong Gilbert who's often oblivious to just how silly he's behaving. The performance is so good and entertaining that I wouldn't be surprised at him getting an outside shot at an Oscar nomination for the role.

As his counterpart, Arthur Sullivan, Allan Corduner ("The Impostors," "Talk Radio") is nearly as good, but in a less showy and crowd pleasing fashion. Notwithstanding that, the chemistry - or purposeful lack thereof - between the two feels just right, and Leigh gives those performers - and the rest of the strong cast - plenty of rich and fun dialogue with which to work. Two sequences of the men working their respective magic on the cast and orchestra are tremendous bits of fun and easily the film's highlights.

Leigh also gives the Gilbert and Sullivan opera, "The Mikado," plenty of time onscreen and some critics and viewers may find some fault there. While it's natural for the film to focus on that opera since it's the basis for what occurs in the second half, Leigh recreates long passages of the work in full, often leaving the audience wondering whether the latter reels of "Topsy-Turvy" were replaced by filmed versions of the opera. It's not a horrible problem - especially since that work is fun to watch and listen to - but some may criticize Leigh for taking the easy way out of filling much of the second half with such footage. And if you're not a big fan of that work, you might the long passages progressively intolerable or unbearable.

The only real problem I had with the film is the way in which it ends. After taking a while to pick up a head of steam and then culminating in the eventual, but full momentum staging of the aforementioned opera, Leigh concludes with three short scenes (including one dealing with abortion talk that comes out of the blue) that only serve to deflate everything built up to that point. While it's obviously purposefully done, the effect is bound to leave some viewers a bit disappointed and/or letdown after such a fun and entertaining ride up to that point.

That aside, the rest of the film is a great romp through the theater world of old. With impressive technical work, strong performances and writer/director Leigh's intelligent script and fluid visual sense, this work should delight theater folk and certainly entertain most of the rest of us. We give "Topsy-Turvy" a 7.5 out of 10.