Breasts equal comedy. I think it was Voltaire who said that, or perhaps Howard Stern.

Consider our first glimpse of Katy Perry in her new documentary-slash-concert film "Katy Perry: Part of Me." The pop star rises to the stage to the screams of young fans wearing an adorably wacky dress with peppermint candy pinwheels placed on -- you guessed it -- her breasts.

The pinwheels, the whipped cream machine gun from her "California Gurls" video -- this is a performer who is not above looking silly for a smile and using her body as a comic device. This explains much of her appeal: She is the Everygirl, the pastor's daughter-turned-pop star, a performer unafraid to be filmed applying pre-concert deodorant.

And in the extravaganza of noise, light and cleavage that is "Katy Perry: Part of Me," a buoyant, for-the-fans-only 3-D documentary, she comes across as the anti-Britney, or a Lady Gaga raised on Hello Kitty and Slurpees, rather than Warhol and Bowie.

Produced by Hollywood big shot Brian Grazer and directed by "Justin Bieber: Never Say Never" producers Dan Cutforth and Jane Lipsitz, the entertaining, if forgettable, film documents Perry's 2011 "Teenage Dream" world tour, her first major outing. During this yearlong jaunt, she became the first female artist to score five No. 1 singles from the same album.

It was also during this tour that her marriage to U.K. funnyman Russell Brand ended. This, incidentally, dominates the final third of "Part of Me" (the film is at least 30 minutes too long), and while our gossipy side is initially intrigued, this drawn-out upset becomes maudlin, especially since we never get to hear Brand's side of the story.

It is the concert footage, then, and, to some extent, the "E! True Hollywood Story"-esque tales of Perry's long road to success, that compel. Seeing young, Christian artist Katy, followed by Alanis-angry Katy and, eventually, "I Kissed a Girl" Katy, is fascinating, whether one is a fan or not.

That I can come away saying I did not regret the experience of watching "Part of Me" says a great deal about the film (perhaps about me, too). I'm one of the many music junkies who have found much of her music quite good -- "Teenage Dreams," "Firework" -- and much of it unmemorable.

But "Part of Me" spends as much time with off-stage Perry as in-the-spotlight Perry. And the person who emerges is sweet, funny and endearing. Look no further than the aforementioned two- or three-second shot of her applying deodorant.

I can't imagine watching Gaga or Madonna (shudder) showing such a thing -- in 3-D, no less -- but it works to demonstrate Perry's innate normalcy and vulnerability.

We spend time with her cantankerous grandma, her frowning but loving parents and her sweet but sycophantic entourage, including her beloved sister, longtime manager and BFF style guy. Think "Truth or Dare" minus the pretension. We also see her sweetly interact with Make-a-Wish kids and watch some "It Gets Better"-style videos from fans.

It's all very nice, but doesn't serve to broaden the film's appeal beyond Perry-ites and, perhaps, their accompanying parents. (I did wonder about the agita Perry's lyrics must give the parents of pre-teen girls: "Let's go all the way tonight/No regrets, just love." I can practically hear the sound of weeping fathers.)

It's unlikely anyone but a die-hard Katy Perry fan will stumble into "Part of Me," and there's nothing wrong with that.

This is one for the fans, and those teenage dreamers will swoon. And considering the singer's love of self-deprecation, I think the kids could do a lot worse.



2 1/2 stars (out of 4)    

STARRING: Katy Perry    

DIRECTORS: Dan Cutforth, Jane Lipsitz    

RUNNING TIME: 93 minutes    

RATING: PG for some suggestive content, language, thematic elements and brief smoking.    

THE LOWDOWN: Pop star Katy Perry's latest tour is brought to the big screen in this backstage-access documentary.