For those living under a rock, "From Justin to Kelly" is the big-screen spin-off of TV's "American Idol," a musical love story starring first season's winner Kelly Clarkson and frizzy-haired runner-up Justin Guarini. Although their characters share the same names as them, they do not play themselves and the story they are in is entirely fictional. Fictional not only because what happens isn't true, but because everything that happens could never occur within the real world. Clarkson and Guarini's goal of making a modern-day version of "Grease" is firmly dashed by the time the first embarrassingly amateurish and forgettable musical number occurs. "Grease" may have been nothing more than lightweight cheese, but at least it was watchable and knew how to carry a tune.

Kelly (Kelly Clarkson) is a struggling singer in an underpopulated Texas bar. Justin (Justin Guarini) is, well, not much of anything. Along with her friends, the vixenish Alexa (Katherine Bailess) and starry-eyed Kaya (Anika Noni Rose), and his best pals, the aspiring hunk Brandon (Greg Siff) and nebbish Eddie (Brian Dietzen), Kelly and Justin travel to Miami for the ultimate spring break and almost instantly share a moment on the beach. It seems Kelly and Justin are meant to be together, and would be if not for the catty Alexa, who wants Justin all to herself.

Directed without much aplomb or anything else by Robert Iscove (2000's "Boys and Girls"), "From Justin to Kelly" is about as terrible as most audiences are probably expecting. Written by Kim Fuller, the mastermind behind 1997's "Spice World," the film is clearly nothing more than a chintzy attempt to cash in on the success of "American Idol." No attempt is made to develop characters, test the acting abilities of its would-be superstars, or even create a premise that makes much sense. None of this would matter, of course, if the song and dance numbers offered any sort of flighty entertainment value, which they don't. The choreography is flat and lifeless; the pop songs are thoroughly disposable, mass-produced trash; and the lip-synching and sound mix have to be some of the worst ever for a big studio motion picture. Some of the musical numbers are so dull and asinine, in fact, that the film realizes it and cuts away from them almost before they get started. Others, such as a climactic beach-set cover of "That's the Way (I Like It)," never seem to end.

Justin Guarini and Kelly Clarkson are the main human attractions, as the rest of the cast are no-names who will likely never be heard from again. Guarini is just plain creepy to look at, while Clarkson shows some star quality that may one day be put to use in a better movie (but don't count on it). Save for a sweet duet near the end, called "Anytime," singers Guarini and Clarkson ironically seem more comfortable when they are just speaking dialogue rather than when they are called upon to lip-synch yet another piece of pop drivel. Together, they fail to ignite even the faintest tinge of romantic chemistry.

2001's "Moulin Rouge" and 2002's "Chicago" may have helped to repopularize the movie musical with modern audiences, but "From Justin to Kelly" is so wretched it may pull the rising genre into an early retirement. The plot's conflict is stupid and condescending, the type that could be solved in five minutes if the characters were written with any sort of sense. They aren't, and so unlucky viewers are forced to endure almost 90 minutes of inane, turgid hogwash. Even the title makes zero sense. "From Justin to Kelly?" "From Big-Screen Bust to the Fiery Depths of Hell" would have been more fitting.