There are plenty of concert scenes woven into "Part of Me." Photo: Paramount Pictures

When Katy Perry kicked off her U.S. tour last June at the Gwinnett Arena, it was noted that, given the spectacle she was engaged in every night, stamina might be a challenge.

In her new movie, “Katy Perry: Part of Me,” opening Thursday, the perky pop princess is shown preparing for that opening night show, putting on deodorant and saying, “I’m nervous, I’m nervous.”

Her then-husband Russell Brand is also glimpsed, edging into the pre-show group huddle.

An hour into the movie, and 200 dates into the tour, Perry is exhausted, both from the nightly grind and from using her few days off to fly cross-countries to meet Brand (in one of the film’s shortcomings, the breakdown of their marriage is set up to portray Perry as the martyr willing to do anything to see her partner and Brand as the guy who couldn’t be bothered to meet her on tour. Who knows if that’s truly their story, but it would have been fair to hear something from Brand, who likely had his own difficulties to endure).

Although “Part of Me” is standard concert-documentary fare – and the 3D element is totally unnecessary, perhaps making the lollipops onstage loom larger, but is that worth the ticket upcharge? – it’s a well-crafted, empathetic portrait of one of pop’s biggest sunbursts.

Of course the camera only sees what Perry allows it to, so while makeup-free moments and unglamorous exercise routines are common sights – stars, they’re just like us! – rare is the moment when Perry is caught alone.

Perhaps that’s the point. Even in the midst of a personal crisis – the dissolution of her marriage – when she can barely breathe from sobbing and has to chin up to perform for tens of thousands of fans in Brazil, Perry is surrounded by an entourage, primarily manager Bradford Cobb, sister Angela Hudson and personal assistant Tamra Natisin.

They all mean well, but you start to wish she could just cry in peace.

But those are the few serious moments in a 90-minute film that deftly weaves footage from her ultra-cool “California Dreams” tour with backstage scenery and interviews with friends and family, including her sassy grandmother who lives in Las Vegas.

Most revealing are the video interviews with an 18-year-old Perry, desperately yearning to break free from her strict upbringing.

“I want to be a leader, but…there’s all those responsibilities,” she says while flopped on a bed, addressing the camera like a media pro and batting her beautiful Disney-esque eyes.

Fans already know her backstory: Raised by religious parents who practiced and preached Pentacostal Christianity (no Lucky Charms could be eaten in the Perry household because “luck” is the work of the devil); a budding Christian music singer who recorded a gospel record at 15; a series of label failures (an old clip of her trying to be the “next Avril Lavigne,” as dictated by one label, is hilarious).

And then… a new label, “I Kissed a Girl” and a new life.

Though Perry admits to not being as involved in religion as her parents – who also appear and profess support despite some disapproval – she still believes in her faith.

Perry always has a smile for fans. Photo: Paramount Pictures

Toward the end of one grueling concert workout, she can be seen mouthing “Thank you, God,” at the ceiling as she’s lowered back under the stage.

But even though you might already know Perry’s history, watching her anything-but-overnight-success story unfold is proof of her talent for those who disregard her as a disposable tart-lette. She writes her own songs, plays the guitar, is involved in every detail of her lavish tour and works herself to exhaustion.

The Perry that pops backstage for well-organized meet-and-greets is always impeccably groomed, like a china doll come to life. Yet her benevolent nature when dealing with fans and that hovering entourage never seems manufactured.

Fans hoping to re-experience the frothy fun of her tour will be satisfied with the appearances of her numerous hits – woven into the movie thematically – including “Hot N Cold,” “E.T.,” “The One That Got Away,” “I Kissed a Girl,” “California Gurls” and the song she said is her favorite to sing, “Firework.” The vocals might be sweetened from their original live incarnations, but hey, aren’t movies about not keeping things real?

“Part of Me” is a valentine to the teens and young adults who idolize Perry, but even those not particularly interested in her life story will find the movie engaging.

Just make sure to watch her facial expressions when standing alone on the perch that elevated her onto the stage at the start of every show. It’s the only time you’ll see Perry alone and witness the emotional rollercoaster that accompanies pop stardom.

Opens July 5 throughout Atlanta. Rated PG (suggestive content, language). Running time: 1:37. 

Check out the trailer below.